WorldWideScience

Sample records for calibrated diversity assay

  1. Calibrated user-friendly reverse transcriptase-PCR assay

    DEFF Research Database (Denmark)

    Bor, M V; Sørensen, B S; Rammer, P;

    1998-01-01

    We report a competitive reverse transcriptase-PCR (RT-PCR) assay and a calibrated user-friendly RT-PCR assay (CURT-PCR) for epidermal growth factor receptor (EGFR) mRNA. A calibrator was prepared from isolated rat liver RNA, and the amount of EGFR mRNA was determined by competitive RT-PCR. In CUR...

  2. On the efficiency calibration of a drum waste assay system

    CERN Document Server

    Dinescu, L; Cazan, I L; Macrin, R; Caragheorgheopol, G; Rotarescu, G

    2002-01-01

    The efficiency calibration of a gamma spectroscopy waste assay system, constructed by IFIN-HH, was performed. The calibration technique was based on the assumption of a uniform distribution of the source activity in the drum and also a uniform sample matrix. A collimated detector (HPGe--20% relative efficiency) placed at 30 cm from the drum was used. The detection limit for sup 1 sup 3 sup 7 Cs and sup 6 sup 0 Co is approximately 45 Bq/kg for a sample of about 400 kg and a counting time of 10 min. A total measurement uncertainty of -70% to +40% was estimated.

  3. Lyophilized standards for the calibration of real time PCR assay for hepatitis C virus RNA

    Institute of Scientific and Technical Information of China (English)

    WANG Lu-nan; WU Jian-min; DENG Wei; SHEN Zi-yu; CHEN Wen-xiang; LI Jin-ming

    2006-01-01

    Background Since October 1997, an international standard for hepatitis C virus (HCV) nucleic acid amplification technology assay, 96/790, has been available. We compared a series of lyophilized standards with known HCV RNA concentrations against the international standard in fluorescence quantitative PCR detection.Methods A series of lyophilized sera were calibrated by ROCHE COBAS AMPLICOR HCV Monitor test against the international standard and sent to various manufacturers to analyse the samples using their own kits.Then calibration curves from the series were compared with that obtained from the external standard calibration curve with the manufacture's series.Results The standard calibration curve with the series of lyophilized serum showed an excellent correlation(R2>0.98), slope and intercept that were similar to those from the manufacture's series. When the standard calibration curve from the series of lyophilized standards were used to define the values of the given sample,lower coefficients of variation between kits from different manufactures were obtained.Conclusion The results showed that the lyophilized standards could be used to setup the standard calibration curve for clinical HCV RNA quantitative PCR detection.

  4. Contactless vector network analysis using diversity calibration with capacitive and inductive coupled probes

    Directory of Open Access Journals (Sweden)

    T. Zelder

    2007-06-01

    Full Text Available Contactless vector network analysis based on a diversity calibration is investigated for the measurement of embedded devices in planar circuits. Conventional contactless measurement systems based on two probes for each measurement port have the disadvantage that the signal-to-noise system dynamics strongly depends on the distance between the contactless probes.

    In order to avoid a decrease in system dynamics a diversity based measurement system is presented. The measurement setup uses one inductive and two capacitive probes. As an inductive probe a half magnetic loop in combination with a broadband balun is introduced. In order to eliminate systematic errors from the measurement results a diversity calibration algorithm is presented. Simulation and measurement results for a one-port configuration are shown.

  5. Formalization, annotation and analysis of diverse drug and probe screening assay datasets using the BioAssay Ontology (BAO.

    Directory of Open Access Journals (Sweden)

    Uma D Vempati

    Full Text Available Huge amounts of high-throughput screening (HTS data for probe and drug development projects are being generated in the pharmaceutical industry and more recently in the public sector. The resulting experimental datasets are increasingly being disseminated via publically accessible repositories. However, existing repositories lack sufficient metadata to describe the experiments and are often difficult to navigate by non-experts. The lack of standardized descriptions and semantics of biological assays and screening results hinder targeted data retrieval, integration, aggregation, and analyses across different HTS datasets, for example to infer mechanisms of action of small molecule perturbagens. To address these limitations, we created the BioAssay Ontology (BAO. BAO has been developed with a focus on data integration and analysis enabling the classification of assays and screening results by concepts that relate to format, assay design, technology, target, and endpoint. Previously, we reported on the higher-level design of BAO and on the semantic querying capabilities offered by the ontology-indexed triple store of HTS data. Here, we report on our detailed design, annotation pipeline, substantially enlarged annotation knowledgebase, and analysis results. We used BAO to annotate assays from the largest public HTS data repository, PubChem, and demonstrate its utility to categorize and analyze diverse HTS results from numerous experiments. BAO is publically available from the NCBO BioPortal at http://bioportal.bioontology.org/ontologies/1533. BAO provides controlled terminology and uniform scope to report probe and drug discovery screening assays and results. BAO leverages description logic to formalize the domain knowledge and facilitate the semantic integration with diverse other resources. As a consequence, BAO offers the potential to infer new knowledge from a corpus of assay results, for example molecular mechanisms of action of perturbagens.

  6. Formalization, annotation and analysis of diverse drug and probe screening assay datasets using the BioAssay Ontology (BAO).

    Science.gov (United States)

    Vempati, Uma D; Przydzial, Magdalena J; Chung, Caty; Abeyruwan, Saminda; Mir, Ahsan; Sakurai, Kunie; Visser, Ubbo; Lemmon, Vance P; Schürer, Stephan C

    2012-01-01

    Huge amounts of high-throughput screening (HTS) data for probe and drug development projects are being generated in the pharmaceutical industry and more recently in the public sector. The resulting experimental datasets are increasingly being disseminated via publically accessible repositories. However, existing repositories lack sufficient metadata to describe the experiments and are often difficult to navigate by non-experts. The lack of standardized descriptions and semantics of biological assays and screening results hinder targeted data retrieval, integration, aggregation, and analyses across different HTS datasets, for example to infer mechanisms of action of small molecule perturbagens. To address these limitations, we created the BioAssay Ontology (BAO). BAO has been developed with a focus on data integration and analysis enabling the classification of assays and screening results by concepts that relate to format, assay design, technology, target, and endpoint. Previously, we reported on the higher-level design of BAO and on the semantic querying capabilities offered by the ontology-indexed triple store of HTS data. Here, we report on our detailed design, annotation pipeline, substantially enlarged annotation knowledgebase, and analysis results. We used BAO to annotate assays from the largest public HTS data repository, PubChem, and demonstrate its utility to categorize and analyze diverse HTS results from numerous experiments. BAO is publically available from the NCBO BioPortal at http://bioportal.bioontology.org/ontologies/1533. BAO provides controlled terminology and uniform scope to report probe and drug discovery screening assays and results. BAO leverages description logic to formalize the domain knowledge and facilitate the semantic integration with diverse other resources. As a consequence, BAO offers the potential to infer new knowledge from a corpus of assay results, for example molecular mechanisms of action of perturbagens.

  7. The use of calibration standards and the correction for sample self-attenuation in gamma-ray nondestructive assay

    Energy Technology Data Exchange (ETDEWEB)

    Parker, J.L.

    1986-11-01

    The efficient use of appropriate calibration standards and the correction for the attenuation of the gamma rays within an assay sample by the sample itself are two important and closely related subjects in gamma-ray nondestructive assay. Much research relating to those subjects has been done in the Nuclear Safeguards Research and Development program at the Los Alamos National Laboratory since 1970. This report brings together most of the significant results of that research. Also discussed are the nature of appropriate calibration standards and the necessary conditions on the composition, size, and shape of the samples to allow accurate assays. Procedures for determining the correction for the sample self-attenuation are described at length including both general principles and several specific useful cases. The most useful concept is that knowing the linear attenuation coefficient of the sample (which can usually be determined) and the size and shape of the sample and its position relative to the detector permits the computation of the correction factor for the self-attenuation. A major objective of the report is to explain how the procedures for determining the self-attenuation correction factor can be applied so that calibration standards can be entirely appropriate without being particularly similar, either physically or chemically, to the items to be assayed. This permits minimization of the number of standards required to assay items with a wide range of size, shape, and chemical composition.

  8. Use of calibration standards and the correction for sample self-attenuation in gamma-ray nondestructive assay

    Energy Technology Data Exchange (ETDEWEB)

    Parker, J.L.

    1984-08-01

    The efficient use of appropriate calibration standards and the correction for the attenuation of the gamma rays within an assay sample by the sample itself are two important and closely related subjects in gamma-ray nondestructive assay. Much research relating to those subjects has been done in the Nuclear Safeguards Research and Development program at the Los Alamos National Laboratory since 1970. This report brings together most of the significant results of that research. Also discussed are the nature of appropriate calibration standards and the necessary conditions on the composition, size, and shape of the samples to allow accurate assays. Procedures for determining the correction for the sample self-attenuation are described at length including both general principles and several specific useful cases. The most useful concept is that knowing the linear attenuation coefficient of the sample (which can usually be determined) and the size and shape of the sample and its position relative to the detector permits the computation of the correction factor for the self-attenuation. A major objective of the report is to explain how the procedures for determining the self-attenuation correction factor can be applied so that calibration standards can be entirely appropriate without being particularly similar, either physically or chemically, to the items to be assayed. This permits minimization of the number of standards required to assay items with a wide range of size, shape, and chemical composition. 17 references, 18 figures, 2 tables.

  9. Dose calibrator manufacturer-dependent bias in assays of ¹²³I.

    Science.gov (United States)

    Bergeron, Denis E; Cessna, Jeffrey T; Golas, Daniel B; Young, Rheannan K; Zimmerman, Brian E

    2014-08-01

    Calibration factors for commercial ionization chambers (i.e. dose calibrators) were determined for a solution of (123)I; the activity was based on the 1976 NBS standard. A link between the NIST standard and the International Reference System (SIR) was established. The two major U.S. dose calibrator manufacturers recommend oppositely biased calibration factors, giving a spread of 11.3% in measured activities. With modern quantitative imaging techniques capable of ≤10% accuracy, this bias for a SPECT nuclide is highly significant.

  10. Rapid Diagnosis of Mycobacterial Infections and Quantitation of Mycobacterium tuberculosis Load by Two Real-Time Calibrated PCR Assays

    Science.gov (United States)

    Broccolo, Francesco; Scarpellini, Paolo; Locatelli, Giuseppe; Zingale, Anna; Brambilla, Anna M.; Cichero, Paola; Sechi, Leonardo A.; Lazzarin, Adriano; Lusso, Paolo; Malnati, Mauro S.

    2003-01-01

    Sensitive and specific techniques to detect and identify Mycobacterium tuberculosis directly in clinical specimens are important for the diagnosis and management of patients with tuberculosis (TB). We developed two real-time PCR assays, based on the IS6110 multicopy element and on the senX3-regX3 intergenic region, which provide a rapid method for the diagnosis of mycobacterial infections. The sensitivity and specificity of both assays were established by using purified DNA from 71 clinical isolates and 121 clinical samples collected from 83 patients, 20 of whom were affected by TB. Both assays are accurate, sensitive, and specific, showing a complementary pattern of Mycobacterium recognition: broader for the IS6110-based assay and restricted to the M. tuberculosis complex for the senX3-regX3-based assay. Moreover, the addition of a synthetic DNA calibrator prior to DNA extraction allowed us to measure the efficiency of DNA recovery and to control for the presence of PCR inhibitors. The mycobacterial burden of the clinical samples, as assessed by direct microscopy, correlates with the M. tuberculosis DNA load measured by the senX3-regX3-based assay. In addition, reduced levels of M. tuberculosis DNA load are present in those patients subjected to successful therapy, suggesting a potential use of this assay for monitoring treatment efficacy. Therefore, these assays represent a fully controlled high-throughput system for the evaluation of mycobacterial burden in clinical specimens. PMID:14532183

  11. Extracellular enzyme activity assay as indicator of soil microbial functional diversity and activity

    DEFF Research Database (Denmark)

    Hendriksen, Niels Bohse; Winding, Anne

    2012-01-01

    Extracellular enzyme activity assay as indicator of soil microbial functional diversity and activity Niels Bohse Hendriksen, Anne Winding. Department of Environmental Science, Aarhus University, 4000 Roskilde, Denmark Soils provide numerous essential ecosystem services such as carbon cycling...... the functional diversity and activity of the microorganisms involved in decomposition processes. Their activity has been measured by the use of fluorogenic model substrates e.g. methylumbelliferyl (MUF) substrates for a number of enzymes involved in the degradation of polysacharides as cellulose, hemicellulose...

  12. A multiplex calibrated real-time PCR assay for quantitation of DNA of EBV-1 and 2.

    Science.gov (United States)

    Gatto, Francesca; Cassina, Giulia; Broccolo, Francesco; Morreale, Giuseppe; Lanino, Edoardo; Di Marco, Eddi; Vardas, Efthiya; Bernasconi, Daniela; Buttò, Stefano; Principi, Nicola; Esposito, Susanna; Scarlatti, Gabriella; Lusso, Paolo; Malnati, Mauro S

    2011-12-01

    Accurate and highly sensitive tests for the diagnosis of active Epstein-Barr virus (EBV) infection are essential for the clinical management of individuals infected with EBV. A calibrated quantitative real-time PCR assay for the measurement of EBV DNA of both EBV-1 and 2 subtypes was developed, combining the detection of the EBV DNA and a synthetic DNA calibrator in a multiplex PCR format. The assay displays a wide dynamic range and a high degree of accuracy even in the presence of 1μg of human genomic DNA. This assay measures with the same efficiency EBV DNA from strains prevalent in different geographic areas. The clinical sensitivity and specificity of the system were evaluated by testing 181 peripheral blood mononuclear cell (PBMCs) and plasma specimens obtained from 21 patients subjected to bone marrow transplantation, 70 HIV-seropositive subjects and 23 healthy controls. Patients affected by EBV-associated post-transplant lymphoprolipherative disorders had the highest frequency of EBV detection and the highest viral load. Persons infected with HIV had higher levels of EBV DNA load in PBMCs and a higher frequency of EBV plasma viremia compared to healthy controls. In conclusion, this new assay provides a reliable high-throughput method for the quantitation of EBV DNA in clinical samples.

  13. The cytokinesis-blocked micronucleus assay: dose-response calibration curve, background frequency in the population and dose estimation.

    Science.gov (United States)

    Rastkhah, E; Zakeri, F; Ghoranneviss, M; Rajabpour, M R; Farshidpour, M R; Mianji, F; Bayat, M

    2016-03-01

    An in vitro study of the dose responses of human peripheral blood lymphocytes was conducted with the aim of creating calibrated dose-response curves for biodosimetry measuring up to 4 Gy (0.25-4 Gy) of gamma radiation. The cytokinesis-blocked micronucleus (CBMN) assay was employed to obtain the frequencies of micronuclei (MN) per binucleated cell in blood samples from 16 healthy donors (eight males and eight females) in two age ranges of 20-34 and 35-50 years. The data were used to construct the calibration curves for men and women in two age groups, separately. An increase in micronuclei yield with the dose in a linear-quadratic way was observed in all groups. To verify the applicability of the constructed calibration curve, MN yields were measured in peripheral blood lymphocytes of two real overexposed subjects and three irradiated samples with unknown dose, and the results were compared with dose values obtained from measuring dicentric chromosomes. The comparison of the results obtained by the two techniques indicated a good agreement between dose estimates. The average baseline frequency of MN for the 130 healthy non-exposed donors (77 men and 55 women, 20-60 years old divided into four age groups) ranged from 6 to 21 micronuclei per 1000 binucleated cells. Baseline MN frequencies were higher for women and for the older age group. The results presented in this study point out that the CBMN assay is a reliable, easier and valuable alternative method for biological dosimetry.

  14. A universally calibrated microplate ferric reducing antioxidant power (FRAP) assay for foods and applications to Manuka honey.

    Science.gov (United States)

    Bolanos de la Torre, Amparo Angelica S; Henderson, Terence; Nigam, Poonam Singh; Owusu-Apenten, Richard K

    2015-05-01

    The ferric reducing antioxidant power (FRAP) assay was recently adapted to a microplate format. However, microplate-based FRAP (mFRAP) assays are affected by sample volume and composition. This work describes a calibration process for mFRAP assays which yields data free of volume effects. From the results, the molar absorptivity (ε) for the mFRAP assay was 141,698 M(-1) cm(-1) for gallic acid, 49,328 M(-1) cm(-1) for ascorbic acid, and 21,606 M(-1) cm(-1) for ammonium ferrous sulphate. The significance of ε (M(-1) cm(-1)) is discussed in relation to mFRAP assay sensitivity, minimum detectable concentration, and the dimensionless FRAP-value. Gallic acid showed 6.6 mol of Fe(2+) equivalents compared to 2.3 mol of Fe(+2) equivalents for ascorbic acid. Application of the mFRAP assay to Manuka honey samples (rated 5+, 10+, 15+, and 18+ Unique Manuka Factor; UMF) showed that FRAP values (0.54-0.76 mmol Fe(2+) per 100g honey) were strongly correlated with UMF ratings (R(2)=0.977) and total phenols content (R(2) = 0.982)whilst the UMF rating was correlated with the total phenols (R(2) = 0.999). In conclusion, mFRAP assay results were successfully standardised to yield data corresponding to 1-cm spectrophotometer which is useful for quality assurance purposes. The antioxidant capacity of Manuka honey was found to be directly related to the UMF rating.

  15. Extracellular Enzyme Activity assay as indicator of soil microbial functional diversity and activity

    DEFF Research Database (Denmark)

    Hendriksen, Niels Bohse; Winding, Anne

    2012-01-01

    Extracellular Enzyme Activity assay as indicator of soil microbial functional diversity and activity Niels Bohse Hendriksen, Anne Winding. Department of Environmental Science, Aarhus University, 4000 Roskilde, Denmark Soil enzymes originate from a variety of organisms, notably fungi and bacteria...... and especially hydrolytic extracellular enzymes are of pivotal importance for decomposition of organic substrates and biogeochemical cycling. Their activity reflects the functional diversity and activity of the microorganisms involved in decomposition processes which are essential processes for soil functioning......, experimental conditions of extraction of enzymes from soils, buffer and pH, substrate concentration, temperature and the necessary controls were optimized and standardized. This has resulted in an optimized standard operating procedure of EEA, which are being tested as an indicator of soil functional diversity...

  16. A High-resolution Typing Assay for Uropathogenic Escherichia coli Based on Fimbrial Diversity.

    Science.gov (United States)

    Ren, Yi; Palusiak, Agata; Wang, Wei; Wang, Yi; Li, Xiao; Wei, Huiting; Kong, Qingke; Rozalski, Antoni; Yao, Zhi; Wang, Quan

    2016-01-01

    Urinary tract infections (UTIs) are one of the most common bacterial infections in humans, causing cystitis, pyelonephritis, and renal failure. Uropathogenic Escherichia coli (UPEC) is the leading cause of UTIs. Accurate and rapid discrimination of UPEC lineages is useful for epidemiological surveillance. Fimbriae are necessary for the adherence of UPEC strains to host uroepithelia, and seem to be abundant and diverse in UPEC strains. By analyzing all the possible fimbrial operons in UPEC strains, we found that closely related strains had similar types of chaperone-usher fimbriae, and the diversity of fimbrial genes was higher than that of multilocus sequence typing (MLST) genes. A typing assay based on the polymorphism of four gene sequences (three fimbrial genes and one housekeeping gene) and the diversity of fimbriae present was developed. By comparison with the MLST, whole-genome sequence (WGS) and fumC/fimH typing methods, this was shown to be accurate and have high resolution, and it was also relatively inexpensive and easy to perform. The assay can supply more discriminatory information for UPEC lineages, and have the potential to be applied in epidemiological surveillance of UPEC isolates.

  17. Increased knowledge of Francisella genus diversity highlights the benefits of optimised DNA-based assays

    Directory of Open Access Journals (Sweden)

    Ahlinder Jon

    2012-09-01

    Full Text Available Abstract Background Recent advances in sequencing technologies offer promising tools for generating large numbers of genomes, larger typing databases and improved mapping of environmental bacterial diversity. However, DNA-based methods for the detection of Francisella were developed with limited knowledge about genetic diversity. This, together with the high sequence identity between several Francisella species, means there is a high risk of false identification and detection of the highly virulent pathogen Francisella tularensis. Moreover, phylogenetic reconstructions using single or limited numbers of marker sequences often result in incorrect tree topologies and inferred evolutionary distances. The recent growth in publicly accessible whole-genome sequences now allows evaluation of published genetic markers to determine optimal combinations of markers that minimise both time and laboratory costs. Results In the present study, we evaluated 38 previously published DNA markers and the corresponding PCR primers against 42 genomes representing the currently known diversity of the genus Francisella. The results highlight that PCR assays for Francisella tularensis are often complicated by low specificity, resulting in a high probability of false positives. A method to select a set of one to seven markers for obtaining optimal phylogenetic resolution or diagnostic accuracy is presented. Conclusions Current multiple-locus sequence-typing systems and detection assays of Francisella, could be improved by redesigning some of the primers and reselecting typing markers. The use of only a few optimally selected sequence-typing markers allows construction of phylogenetic topologies with almost the same accuracy as topologies based on whole-genome sequences.

  18. Genetic diversity and relationships in mulberry (genus Morus as revealed by RAPD and ISSR marker assays

    Directory of Open Access Journals (Sweden)

    Thangavelu K

    2004-01-01

    Full Text Available Abstract Background The genus Morus, known as mulberry, is a dioecious and cross-pollinating plant that is the sole food for the domesticated silkworm, Bombyx mori. Traditional methods using morphological traits for classification are largely unsuccessful in establishing the diversity and relationships among different mulberry species because of environmental influence on traits of interest. As a more robust alternative, PCR based marker assays including RAPD and ISSR were employed to study the genetic diversity and interrelationships among twelve domesticated and three wild mulberry species. Results RAPD analysis using 19 random primers generated 128 discrete markers ranging from 500–3000 bp in size. One-hundred-nineteen of these were polymorphic (92%, with an average of 6.26 markers per primer. Among these were a few putative species-specific amplification products which could be useful for germplasm classification and introgression studies. The ISSR analysis employed six anchored primers, 4 of which generated 93 polymorphic markers with an average of 23.25 markers per primer. Cluster analysis of RAPD and ISSR data using the WINBOOT package to calculate the Dice coefficient resulted into two clusters, one comprising polyploid wild species and the other with domesticated (mostly diploid species. Conclusion These results suggest that RAPD and ISSR markers are useful for mulberry genetic diversity analysis and germplasm characterization, and that putative species-specific markers may be obtained which can be converted to SCARs after further studies.

  19. A comparison of two measures of HIV diversity in multi-assay algorithms for HIV incidence estimation.

    Directory of Open Access Journals (Sweden)

    Matthew M Cousins

    Full Text Available Multi-assay algorithms (MAAs can be used to estimate HIV incidence in cross-sectional surveys. We compared the performance of two MAAs that use HIV diversity as one of four biomarkers for analysis of HIV incidence.Both MAAs included two serologic assays (LAg-Avidity assay and BioRad-Avidity assay, HIV viral load, and an HIV diversity assay. HIV diversity was quantified using either a high resolution melting (HRM diversity assay that does not require HIV sequencing (HRM score for a 239 base pair env region or sequence ambiguity (the percentage of ambiguous bases in a 1,302 base pair pol region. Samples were classified as MAA positive (likely from individuals with recent HIV infection if they met the criteria for all of the assays in the MAA. The following performance characteristics were assessed: (1 the proportion of samples classified as MAA positive as a function of duration of infection, (2 the mean window period, (3 the shadow (the time period before sample collection that is being assessed by the MAA, and (4 the accuracy of cross-sectional incidence estimates for three cohort studies.The proportion of samples classified as MAA positive as a function of duration of infection was nearly identical for the two MAAs. The mean window period was 141 days for the HRM-based MAA and 131 days for the sequence ambiguity-based MAA. The shadows for both MAAs were <1 year. Both MAAs provided cross-sectional HIV incidence estimates that were very similar to longitudinal incidence estimates based on HIV seroconversion.MAAs that include the LAg-Avidity assay, the BioRad-Avidity assay, HIV viral load, and HIV diversity can provide accurate HIV incidence estimates. Sequence ambiguity measures obtained using a commercially-available HIV genotyping system can be used as an alternative to HRM scores in MAAs for cross-sectional HIV incidence estimation.

  20. Field calibration of blowfly-derived DNA against traditional methods for assessing mammal diversity in tropical forests.

    Science.gov (United States)

    Lee, Ping-Shin; Gan, Han Ming; Clements, Gopalasamy Reuben; Wilson, John-James

    2016-11-01

    Mammal diversity assessments based on DNA derived from invertebrates have been suggested as alternatives to assessments based on traditional methods; however, no study has field-tested both approaches simultaneously. In Peninsular Malaysia, we calibrated the performance of mammal DNA derived from blowflies (Diptera: Calliphoridae) against traditional methods used to detect species. We first compared five methods (cage trapping, mist netting, hair trapping, scat collection, and blowfly-derived DNA) in a forest reserve with no recent reports of megafauna. Blowfly-derived DNA and mist netting detected the joint highest number of species (n = 6). Only one species was detected by multiple methods. Compared to the other methods, blowfly-derived DNA detected both volant and non-volant species. In another forest reserve, rich in megafauna, we calibrated blowfly-derived DNA against camera traps. Blowfly-derived DNA detected more species (n = 11) than camera traps (n = 9), with only one species detected by both methods. The rarefaction curve indicated that blowfly-derived DNA would continue to detect more species with greater sampling effort. With further calibration, blowfly-derived DNA may join the list of traditional field methods. Areas for further investigation include blowfly feeding and dispersal biology, primer biases, and the assembly of a comprehensive and taxonomically-consistent DNA barcode reference library.

  1. Genetic diversity in Silene sennenii Pau (Caryophyllaceae assayed through DNA-based techniques

    Directory of Open Access Journals (Sweden)

    Blanché, C.

    2012-12-01

    Full Text Available Silene sennenii is a narrow endemic species from the NE of the Iberian Peninsula. It is considered as EN (“Endangered” according to the IUCN criteria and is under legal protection in Catalonia. In the present work we report an assay using three different approaches for surveying the genetic diversity in this rare, endangered campion: analysis of chloroplast haplotypes, AFLPs and transferability of microsatellites previously developed for Silene latifolia. None of the nine chloroplast regions sequenced showed any variability. Five out of the 21 microsatellite loci tested were polymorphic although more loci are required in order to perform a robust population genetics study. Regarding the AFLP analysis, five out of the 26 pairs of primers tested exhibited moderate levels of variability and therefore they could be useful for further investigating the genetic structure of S. sennenii. Although preliminary, our results based on three different genetic markers are in agreement with the low values of genetic variation already reported for this species employing allozymes.Silene sennenii es una especie endémica, circunscrita a un área extremadamente reducida al NE de la Península Ibérica. Está catalogada como EN («En Peligro» según criterios UICN y se encuentra legalmente protegida en Cataluña. En el presente trabajo se expone el ensayo de tres aproximaciones diferentes al estudio de su diversidad genética: análisis de haplotipos cloroplásticos, AFLPs y transferibilidad de microsatélites diseñados previamente para Silene latifolia. Ninguna de las nueve regiones cloroplásticas secuenciadas ha presentado variabilidad. Se han obtenido cinco loci microsatélites polimórficos de los 21 ensayados, cantidad insuficiente para llevar a cabo un estudio robusto sobre genética poblacional. En cuanto a AFLPs, cinco combinaciones de cebadores de las 26 probadas han mostrado niveles moderados de variabilidad siendo así útiles para posteriores

  2. Interpreting sperm DNA damage in a diverse range of mammalian sperm by means of the two-tailed comet assay

    Directory of Open Access Journals (Sweden)

    Elva I eCortes-Gutierrez

    2014-11-01

    Full Text Available Sperm DNA damage is associated with fertilization failure, impaired pre-and post- embryo implantation and poor pregnancy outcome. A series of methodologies to assess DNA damage in spermatozoa have been developed but most are unable to differentiate between single-stranded DNA breaks (SSBs and double-stranded DNA breaks (DSBs on the same sperm cell. The two-dimensional Two-Tailed Comet assay (TT-comet protocol highlighted in this review overcomes this limitation and emphasizes the importance in accounting for difference in sperm protamine composition at a species-specific level for the appropriate preparation of the assay. The TT-comet is a modification of the original comet assay that uses a two dimensional electrophoresis to allow for the simultaneous evaluation of relatively high numbers of DSBs and SSBs in mammalian spermatozoa. Here we have compiled a retrospective overview of how the TT-comet assay has been used to investigate the structure and function of sperm DNA across a diverse range of mammalian species (eutheria, metatheria and prototheria. When conducted as part of the TT-comet assay, we discuss how (a the alkaline comet single assay has been used to help understand the constitutive and transient changes in DNA structure associated with chromatin packing, (b the capacity of the TT-comet to differentiate between the presence of SSBs and DSBs (c and the possible implications of SSBs or DSBs for the assessment of infertility.

  3. Toward a universal carbonate clumped isotope calibration: Diverse synthesis and preparatory methods suggest a single temperature relationship

    Science.gov (United States)

    Kelson, Julia R.; Huntington, Katharine W.; Schauer, Andrew J.; Saenger, Casey; Lechler, Alex R.

    2017-01-01

    does not measurably change with either the precipitation methods used in this study or acid digestion temperature. This leaves phosphoric acid preparation, CO2 gas purification, and/or data reduction methods as the possible sources of the discrepancy among published calibrations. In particular, the use of appropriate 17O corrections has the potential to reduce disagreement among calibrations. Our study nearly doubles the available synthetic carbonate calibration data for Δ47 thermometry (adding 56 samples to the 74 previously published samples). This large population size creates a robust calibration that enables us to examine the potential for calibration slope aliasing due to small sample size. The similarity of Δ47 values among carbonates precipitated under such diverse conditions suggests that many natural samples grown at 4-85 °C in moderate pH conditions (6-10) may also be described by our Δ47-temperature relationship.

  4. Electroluminescent TCC, C3dg and fB/Bb epitope assays for profiling complement cascade activation in vitro using an activated complement serum calibration standard.

    Science.gov (United States)

    van Vuuren, B Jansen; Bergseth, G; Mollnes, T E; Shaw, A M

    2014-01-15

    Electroluminescent assays for epitopes on the complement components C3dg, terminal complement complex (TCC) and factor B/Bb (fB/Bb) have been developed with capture and detection antibodies to produce detection limits C3dg=91±9ng/mL, TCC=3±0.1ng/mL and fB=55.7±0.1ng/mL. The assay performance was assessed against a series of zymosan and heat aggregated IgG (HAIgG) in vitro activations of complement using a calibrated activated complement serum (ACS) as calibration standard. The ACS standard was stable within 20% accuracy over a 6-month period with freeze-thaw cycles as required. Differential activation of the complement cascade was observed for TCC showing a pseudo-first order formation half-life of 3.5h after activation with zymosan. The C3dg activation fragment indicates a 10% total activation for both activation agents. The kinetic-epitope analysis for fB indicates that the capture epitope is on the fB/Bb protein fragment which can then become covered by the formation of C3bBb or C3bBbP complexes during the time course of the cascade.

  5. Diploid Musa acuminata genetic diversity assayed with sequence-tagged microsatellite sites.

    Science.gov (United States)

    Grapin, A; Noyer, J L; Carreel, F; Dambier, D; Baurens, F C; Lanaud, C; Lagoda, P J

    1998-06-01

    The sequence-tagged microsatellite site (STMS) discrimination potential was explored using nine microsatellite primer pairs. STMS polymorphism was assayed by nonradioactive urea-polyacrylamide gel electrophoresis. Genetic relationships were examined among 59 genotypes of wild or cultivated accessions of diploid Musa acuminata. The organization of the subspecies was confirmed and some clone relationships were clarified.

  6. Determination of folate concentrations in diverse potato germplasm using a trienzyme extraction and microbiological assay

    Science.gov (United States)

    We determined total folate concentrations of potato tubers from 67 cultivars, advanced breeding lines, or wild species. Folates were extracted by a tri-enzyme treatment and analyzed by using a Lactobacillus rhamnosus microbiological assay. Folate concentrations varied from 521 ± 96 to 1373 ± 230 ng/...

  7. Calibration and validation of the {sup 14}C-labelled polyethylene glycol-binding assay for tannins in tropical browse

    Energy Technology Data Exchange (ETDEWEB)

    Mlambo, V. [Animal Production Unit, FAO/IAEA Agriculture and Biotechnology Laboratory, Seibersdorf (Austria)]. E-mail: vmlambo@agric.uniswa.sz; Makkar, H.P.S. [Animal Production and Health Section, Joint FAO/IAEA Division of Nuclear Techniques in Agriculture and Food, International Atomic Energy Agency, Vienna (Austria)

    2005-08-19

    This study evaluates the radiolabelled polyethylene glycol (PEG)-binding procedure [Silanikove, N., Shinder, D., Gilboa, N., Eyal, M., Nitsan, Z., 1996. Polyethylene glycol-binding to plant samples as an assay for the biological effects of tannins: predicting the negative effects of tannins in Mediterranean browse on rumen degradation. J. Agric. Food Chem. 44, 3230-3234] for tannin analysis, using 27 tropical browse plants. In this method, the amount of PEG bound to a plant sample is assumed to be a reflection of its tannin content. The method was modified to exclude the use of non-tanniniferous substrate for estimating non-specific binding (NSB) in tannin-containing substrates. Non-specific binding values varied widely (0.4-2.8 mg PEG/100 mg DM tannin-free substrate) when the tannin-free substrate was changed from wheat straw to either rye grass or maize shoots. We therefore propose a modified radiolabelled PEG-binding method to estimate the level of PEG-binding (PEGb) to tannin-containing foliage without using tannin-free substrate to correct for non-specific binding. In this approach, incremental levels of each tanniniferous substrate were used to generate PEGb values. The resultant linear response was analysed and tannin activity was expressed as the slope of the response curve (PEGbSlope) observed for each substrate. The slope takes into account the non-specific binding in each substrate, thus PEGbSlope does not require correction for NSB using tannin-free samples. This approach improved the correlation between PEGb and the {sup 125}I-labelled bovine serum albumin precipitation assay. Relationships between the modified PEG-binding assay and radiolabelled bovine serum albumin assay, in vitro tannin bioassay and colorimetric assays are presented. (author)

  8. A multilocus assay reveals high nucleotide diversity and limited differentiation among Scandinavian willow grouse (Lagopus lagopus

    Directory of Open Access Journals (Sweden)

    Quintela Maria

    2008-12-01

    Full Text Available Abstract Background There is so far very little data on autosomal nucleotide diversity in birds, except for data from the domesticated chicken and some passerines species. Estimates of nucleotide diversity reported so far in birds have been high (~10-3 and a likely explanation for this is the generally higher effective population sizes compared to mammals. In this study, the level of nucleotide diversity has been examined in the willow grouse, a non-domesticated bird species from the order Galliformes, which also holds the chicken. The willow grouse (Lagopus lagopus has an almost circumpolar distribution but is absent from Greenland and the north Atlantic islands. It primarily inhabits tundra, forest edge habitats and sub-alpine vegetation. Willow grouse are hunted throughout its range, and regionally it is a game bird of great cultural and economical importance. Results We sequenced 18 autosomal protein coding loci from approximately 15–18 individuals per population. We found a total of 127 SNP's, which corresponds to 1 SNP every 51 bp. 26 SNP's were amino acid replacement substitutions. Total nucleotide diversity (πt was between 1.30 × 10-4 and 7.66 × 10-3 (average πt = 2.72 × 10-3 ± 2.06 × 10-3 and silent nucleotide diversity varied between 4.20 × 10-4and 2.76 × 10-2 (average πS = 9.22 × 10-3 ± 7.43 × 10-4. The synonymous diversity is approximately 20 times higher than in humans and two times higher than in chicken. Non-synonymous diversity was on average 18 times lower than the synonymous diversity and varied between 0 and 4.90 × 10-3 (average πa = 5.08 × 10-4 ± 7.43 × 103, which suggest that purifying selection is strong in these genes. FST values based on synonymous SNP's varied between -5.60 × 10-4 and 0.20 among loci and revealed low levels of differentiation among the four localities, with an overall value of FST = 0.03 (95% CI: 0.006 – 0.057 over 60 unlinked loci. Non-synonymous SNP's gave similar results. Low

  9. Sequence diversity within the HA-1 gene as detected by melting temperature assay without oligonucleotide probes

    Directory of Open Access Journals (Sweden)

    Mattiuz Pier

    2005-10-01

    Full Text Available Abstract Background The minor histocompatibility antigens (mHags are self-peptides derived from common cellular proteins and presented by MHC class I and II molecules. Disparities in mHags are a potential risk for the development of graft-versus-host disease (GvHD in the recipients of bone marrow from HLA-identical donors. Two alleles have been identified in the mHag HA-1. The correlation between mismatches of the mHag HA-1 and GvHD has been suggested and methods to facilitate large-scale testing were afterwards developed. Methods We used sequence specific primer (SSP PCR and direct sequencing to detect HA-1 gene polymorphisms in a sample of 131 unrelated Italian subjects. We then set up a novel melting temperature (Tm assay that may help identification of HA-1 alleles without oligonucleotide probes. Results We report the frequencies of HA-1 alleles in the Italian population and the presence of an intronic 5 base-pair deletion associated with the immunogeneic allele HA-1H. We also detected novel variable sites with respect to the consensus sequence of HA-1 locus. Even though recombination/gene conversion events are documented, there is considerable linkage disequilibrium in the data. The gametic associations between HA-1R/H alleles and the intronic 5-bp ins/del polymorphism prompted us to try the Tm analysis with SYBR® Green I. We show that the addition of dimethylsulfoxide (DMSO during the assay yields distinct patterns when amplicons from HA-1H homozygotes, HA-1R homozygotes, and heterozygotes are analysed. Conclusion The possibility to use SYBR® Green I to detect Tm differences between allelic variants is attractive but requires great caution. We succeeded in allele discrimination of the HA-1 locus using a relatively short (101 bp amplicon, only in the presence of DMSO. We believe that, at least in certain assets, Tm assays may benefit by the addition of DMSO or other agents affecting DNA strand conformation and stability.

  10. Comparison of ordinary, weighted, and generalized least-squares straight-line calibrations for LC-MS-MS, GC-MS, HPLC, GC, and enzymatic assay.

    Science.gov (United States)

    Duer, Wayne C; Ogren, Paul J; Meetze, Alison; Kitchen, Chester J; Von Lindern, Ryan; Yaworsky, Dustin C; Boden, Christopher; Gayer, Jeffery A

    2008-06-01

    The impact of experimental errors in one or both variables on the use of linear least-squares was investigated for method calibrations (response = intercept plus slope times concentration, or equivalently, Y = a(1) + a(2)X ) frequently used in analytical toxicology. In principle, the most reliable calibrations should consider errors from all sources, but consideration of concentration (X) uncertainties has not been common due to complex fitting algorithm requirements. Data were obtained for liquid chromatography-tandem mass spectrometry, gas chromatography-mass spectrometry, high-performance liquid chromatography, gas chromatography, and enzymatic assay. The required experimental uncertainties in response were obtained from replicate measurements. The required experimental uncertainties in concentration were determined from manufacturers' furnished uncertainties in stock solutions coupled with uncertainties imparted by dilution techniques. The mathematical fitting techniques used in the investigation were ordinary least-squares, weighted least-squares (WOLS), and generalized least-squares (GLS). GLS best-fit results, obtained with an efficient iteration algorithm implemented in a spreadsheet format, are used with a modified WOLS-based formula to derive reliable uncertainties in calculated concentrations. It was found that while the values of the intercepts and slopes were not markedly different for the different techniques, the derived uncertainties in parameters were different. Such differences can significantly affect the predicted uncertainties in concentrations derived from the use of the different linear least-squares equations.

  11. A simple cell-based assay reveals that diverse neuropsychiatric risk genes converge on primary cilia.

    Directory of Open Access Journals (Sweden)

    Aaron Marley

    Full Text Available Human genetic studies are beginning to identify a large number of genes linked to neuropsychiatric disorders. It is increasingly evident that different genes contribute to risk for similar syndromes and, conversely, the same genes or even the same alleles cross over traditional diagnostic categories. A current challenge is to understand the cellular biology of identified risk genes. However, most genes associated with complex neuropsychiatric phenotypes are not related through a known biochemical pathway, and many have an entirely unknown cellular function. One possibility is that diverse disease-linked genes converge at a higher-level cellular structure. The synapse is already known to be one such convergence, and emerging evidence suggests the primary cilium as another. Because many genes associated with neuropsychiatric illness are expressed also outside the nervous system, as are cilia, we tested the hypothesis that such genes affect conserved features of the primary cilium. Using RNA interference to test 41 broadly expressed candidate genes associated with schizophrenia, bipolar affective disorder, autism spectrum disorder and intellectual disability, we found 20 candidates that reduce ciliation in NIH3T3 cells when knocked down, and three whose manipulation increases cilia length. Three of the candidate genes were previously implicated in cilia formation and, altogether, approximately half of the candidates tested produced a ciliary phenotype. Our results support the hypothesis that primary cilia indeed represent a conserved cellular structure at which the effects of diverse neuropsychiatric risk genes converge. More broadly, they suggest a relatively simple cell-based approach that may be useful for exploring the complex biological underpinnings of neuropsychiatric disease.

  12. Use of a high resolution melting (HRM assay to compare gag, pol, and env diversity in adults with different stages of HIV infection.

    Directory of Open Access Journals (Sweden)

    Matthew M Cousins

    Full Text Available BACKGROUND: Cross-sectional assessment of HIV incidence relies on laboratory methods to discriminate between recent and non-recent HIV infection. Because HIV diversifies over time in infected individuals, HIV diversity may serve as a biomarker for assessing HIV incidence. We used a high resolution melting (HRM diversity assay to compare HIV diversity in adults with different stages of HIV infection. This assay provides a single numeric HRM score that reflects the level of genetic diversity of HIV in a sample from an infected individual. METHODS: HIV diversity was measured in 203 adults: 20 with acute HIV infection (RNA positive, antibody negative, 116 with recent HIV infection (tested a median of 189 days after a previous negative HIV test, range 14-540 days, and 67 with non-recent HIV infection (HIV infected >2 years. HRM scores were generated for two regions in gag, one region in pol, and three regions in env. RESULTS: Median HRM scores were higher in non-recent infection than in recent infection for all six regions tested. In multivariate models, higher HRM scores in three of the six regions were independently associated with non-recent HIV infection. CONCLUSIONS: The HRM diversity assay provides a simple, scalable method for measuring HIV diversity. HRM scores, which reflect the genetic diversity in a viral population, may be useful biomarkers for evaluation of HIV incidence, particularly if multiple regions of the HIV genome are examined.

  13. Role of Assay Type in Determining Free 25-Hydroxyvitamin D Levels in Diverse Populations

    Energy Technology Data Exchange (ETDEWEB)

    Nielson, Carrie M.; Jones, Kerry S.; Chun, Rene F.; Jacobs, Jon; Wang, Ying; Hewison, Martin; Adams, John S.; Swanson, Christine M.; Lee, Christine G.; Vanderschueren, Dirk; Pauwels, Steven; Prentice, Ann; Smith, Richard D.; Shi, Tujin; Gao, Yuqian; Zmuda, Joseph M.; Lapidus, Jodi; Cauley, Jane A.; Bouillon, Roger; Schoenmakers, Inez; Orwoll, Eric S.

    2016-04-28

    Serum 25-hydroxyvitamin D (25OHD) is the most frequently used marker of vitamin D status. Low 25OHD is associated with bone loss, fractures {Cauley, 2010 #1516;Ensrud, 2009 #1517}, and other adverse health outcomes {Theodoratou, 2014 #1518}. Most extra renal tissues only have access to free 25OHD, and free 25OHD concentration is thus a plausible biomarker of 25OHD availability and function {Johnsen, 2014 #1443;Chun, 2014 #1343}. Stronger associations with free or bioavailable 25OHD than with total 25OHD were reported for serum calcium, parathyroid hormone (PTH) {Bhan, 2012 #1124} and bone mineral density (BMD) {Powe, 2011 #1129}. These findings have led to the suggestion that free or bioavailable 25OHD may provide a more clinically relevant measure of tissue 25OHD availability and vitamin D status {Powe, 2013 #1369; Holick NEJM 2013 editorial}. The US Preventive Services Task Force (LeFevre 2015) recently pointed to the gap in research regarding bioavailable and free 25OHD and noted the possibility that these may be better markers of tissue 25OHD availability. Free 25OHD is conventionally calculated from the concentrations of total 25OHD, vitamin D binding protein (DBP) and albumin, with or without a factor accounting for DBP genotype-specific binding affinities {Bouillon, 1981 #1207;Chun, 2012 #1143; Powe, 2011 #1129;Johnsen, 2014 #1443}. DBP—or Group specific component (GC) {Hirschfeld, 1959 #1468}—polymorphisms (rs4588 and rs7041) give rise to three major polymorphic isoforms of DBP, GC-1F, GC-1S and GC-2, the frequencies of which differ globally, with GC-1F alleles more common in populations of African descent {Kambou, 1986 #1122}. Although DBP is a primary component of free and bioavailable 25OHD calculations, substantial variation in DBP between assays has been noted (Powe suggest to cite here previous publications as in previous version of this Ms). Using DBP measured by a monoclonal antibody Powe et al. {Powe, 2013 #1369} concluded that calculated free

  14. New recombinant cyclohexylamine oxidase variants for deracemization of secondary amines by orthogonally assaying designed mutants with structurally diverse substrates

    Science.gov (United States)

    Li, Guangyue; Yao, Peiyuan; Cong, Peiqian; Ren, Jie; Wang, Lei; Feng, Jinhui; Lau, Peter C. K.; Wu, Qiaqing; Zhu, Dunming

    2016-05-01

    To further expand the substrate range of the cyclohexylamine oxidase (CHAO) from Brevibacterium oxydans, a library of diverse mutants was created and assayed toward a group of structurally diverse substrates. Among them, mutants T198A and M226A exhibited enhanced activity relative to wt CHAO for most (S)-enantiomers of primary amines and some secondary amines. While mutants T198I, L199I, L199F, M226I and M226T were more active than wt CHAO toward the primary amines, mutants T198F, L199T, Y321A, Y321T, Y321I and Y321F enhanced the enzyme activity toward the secondary amines. In particular, mutant Y321I displayed an enhanced catalytic efficiency toward 1-(4-methoxybenzyl)-1, 2, 3, 4, 5, 6, 7, 8-octahydroisoquinoline (13). Whereas a double mutant, Y321I/M226T, acted on (S)-N-(prop-2-yn-1-yl)-2, 3-dihydro-1H-inden-1-amine [(S)-8]. Since (R)-8 is an irreversible inhibitor of monoamine oxidase and (S)-13 is an intermediate of dextromethorphan, a cough suppressant drug, deracemizations of 8 and 13 were carried out with crude enzyme extracts of the respective mutants. This resulted in 51% and 78% isolated yields of (R)-8 and (S)-13, respectively, each with high enantiomeric excess (93% and 99% ee). The results demonstrated the application potential of the evolved CHAO mutants in drug synthesis requiring chiral secondary amines.

  15. Editor's Highlight: Analysis of the Effects of Cell Stress and Cytotoxicity on In Vitro Assay Activity Across a Diverse Chemical and Assay Space.

    Science.gov (United States)

    Judson, Richard; Houck, Keith; Martin, Matt; Richard, Ann M; Knudsen, Thomas B; Shah, Imran; Little, Stephen; Wambaugh, John; Woodrow Setzer, R; Kothya, Parth; Phuong, Jimmy; Filer, Dayne; Smith, Doris; Reif, David; Rotroff, Daniel; Kleinstreuer, Nicole; Sipes, Nisha; Xia, Menghang; Huang, Ruili; Crofton, Kevin; Thomas, Russell S

    2016-08-01

    Chemical toxicity can arise from disruption of specific biomolecular functions or through more generalized cell stress and cytotoxicity-mediated processes. Here, responses of 1060 chemicals including pharmaceuticals, natural products, pesticidals, consumer, and industrial chemicals across a battery of 815 in vitro assay endpoints from 7 high-throughput assay technology platforms were analyzed in order to distinguish between these types of activities. Both cell-based and cell-free assays showed a rapid increase in the frequency of responses at concentrations where cell stress/cytotoxicity responses were observed in cell-based assays. Chemicals that were positive on at least 2 viability/cytotoxicity assays within the concentration range tested (typically up to 100 μM) activated a median of 12% of assay endpoints whereas those that were not cytotoxic in this concentration range activated 1.3% of the assays endpoints. The results suggest that activity can be broadly divided into: (1) specific biomolecular interactions against one or more targets (eg, receptors or enzymes) at concentrations below which overt cytotoxicity-associated activity is observed; and (2) activity associated with cell stress or cytotoxicity, which may result from triggering specific cell stress pathways, chemical reactivity, physico-chemical disruption of proteins or membranes, or broad low-affinity non-covalent interactions. Chemicals showing a greater number of specific biomolecular interactions are generally designed to be bioactive (pharmaceuticals or pesticidal active ingredients), whereas intentional food-use chemicals tended to show the fewest specific interactions. The analyses presented here provide context for use of these data in ongoing studies to predict in vivo toxicity from chemicals lacking extensive hazard assessment.

  16. Platelet-induced thrombin generation by the calibrated automated thrombogram assay is increased in patients with essential thrombocythemia and polycythemia vera.

    Science.gov (United States)

    Panova-Noeva, Marina; Marchetti, Marina; Spronk, Henri Maria; Russo, Laura; Diani, Erika; Finazzi, Guido; Finazzi, Good; Salmoiraghi, Silvia; Rambaldi, Alessandro; Rambaldi, Aueesandrd; Barbui, Tiziano; Barbui, Titiano; Ten Cate, Hugo; Ten Cate, Huao; Falanga, Anna

    2011-04-01

    The platelet contribution to the thrombophilic state of patients with myeloproliferative neoplasms (MPNs), i.e., essential thrombocythemia (ET) and polycythemia vera (PV), remains uncertain. In this study we aimed to characterize the thrombin generation (TG) potential expressed by platelets from these subjects, compare it to normal platelets, and identify what factors might be responsible for platelet TG. In a group of 140 MPN patients (80 ET and 60 PV) and 72 healthy subjects, we measured the global procoagulant potential of platelet-rich plasma (PRP) utilizing the TG assay by the calibrated automated thrombogram (CAT). To characterize the procoagulant contribution of platelets in PRP, the TG of both isolated platelets and platelet-poor plasma was measured, and the platelet surface expression of TF was determined. Finally, the activation status of platelets was assessed by the levels of P-selectin expressed on platelet surface. MPN patients had significantly increased PRP and isolated platelet TG potential compared to controls. This was associated to the occurrence of platelet activation. Patients carriers of the JAK2V617F mutation showed the highest values of TG and platelet surface TF and P-selectin. Platelet TG potential was significantly lower in hydroxyurea(HU) compared to non-HU-treated patients and was lowest in HU-treated JAK2V617F carriers. In subjects not receiving HU, platelet TG significantly increased by JAK2V617F allele burden increment (P < 0.05).This study demonstrates a platelet-dependent form of hypercoagulability in MPN patients, particularly in those carriers of the JAK2V617F mutation. The cytoreductive therapy with HU significantly affects this prothrombotic phenotype.

  17. Type-specific PCR assays for Babesia bovis msa-1 genotypes in Asia: Revisiting the genetic diversity in Sri Lanka, Mongolia, and Vietnam.

    Science.gov (United States)

    Liyanagunawardena, Nilukshi; Sivakumar, Thillaiampalam; Kothalawala, Hemal; Silva, Seekkuge Susil Priyantha; Battsetseg, Badgar; Lan, Dinh Thi Bich; Inoue, Noboru; Igarashi, Ikuo; Yokoyama, Naoaki

    2016-01-01

    Babesia bovis is the most virulent Babesia organism, resulting in a high mortality rate in cattle. The genetic diversity of B. bovis merozoite surface antigens (MSAs), such as MSA-1, MSA-2b, and MSA-2c, might be linked to altered immune profiles in the host animals. The present study aimed to develop type-specific PCR assays for Asian msa-1 genotypes, thereby re-analyzing the genetic diversity of msa-1 in Sri Lanka, Mongolia, and Vietnam. Specific primers were designed for nine Asian msa-1 genotypes, which had been detected based on the phylogeny constructed using msa-1 gene sequences retrieved from the GenBank database. Specificity of the type-specific PCR assays was confirmed using plasmids containing the inserts of msa-1 gene fragments that represent Asian genotypes. Furthermore, no amplicons were observed by these PCR assays when DNA samples of Babesia bigemina, Babesia ovata, Theileria annulata, Theileria orientalis, Trypanosoma evansi, Trypanosoma theileri, Anaplasma marginale, and Anaplasma bovis, and non-infected bovine blood were analyzed. In total, 109 B. bovis-positive blood DNA samples sourced from Sri Lanka (44 cattle), Mongolia (26 cattle), and Vietnam (23 cattle and 16 water buffaloes) were then screened by the type-specific PCR assays. The sequences derived from all of the PCR amplicons were phylogenetically analyzed. Out of 109 DNA samples, 23 (20 from cattle and 3 from water buffaloes) were positive for at least one genotype. In agreement with previous studies, five and four different genotypes were detected among the DNA samples from Sri Lanka and Vietnam, respectively. In contrast, four genotypes, including three novel genotypes, were detected from Mongolia. Five DNA samples were found to be co-infected with multiple genotypes. The sequences of the PCR amplicons clustered phylogenetically within the corresponding clades. These findings indicated that the type-specific PCR assays described herein are useful for the determination of genotypic

  18. Calibrating snakehead diversity with DNA barcodes: expanding taxonomic coverage to enable identification of potential and established invasive species.

    Directory of Open Access Journals (Sweden)

    Natasha R Serrao

    Full Text Available Detecting and documenting the occurrence of invasive species outside their native range requires tools to support their identification. This can be challenging for taxa with diverse life stages and/or problematic or unresolved morphological taxonomies. DNA barcoding provides a potent method for identifying invasive species, as it allows for species identification at all life stages, including fragmentary remains. It also provides an efficient interim taxonomic framework for quantifying cryptic genetic diversity by parsing barcode sequences into discontinuous haplogroup clusters (typical of reproductively isolated species and labelling them with unique alphanumeric identifiers. Snakehead fishes are a diverse group of opportunistic predators endemic to Asia and Africa that may potentially pose significant threats as aquatic invasive species. At least three snakehead species (Channa argus, C. maculata, and C. marulius are thought to have entered North America through the aquarium and live-food fish markets, and have established populations, yet their origins remain unclear. The objectives of this study were to assemble a library of DNA barcode sequences derived from expert identified reference specimens in order to determine the identity and aid invasion pathway analysis of the non-indigenous species found in North America using DNA barcodes. Sequences were obtained from 121 tissue samples representing 25 species and combined with public records from GenBank for a total of 36 putative species, which then partitioned into 49 discrete haplogroups. Multiple divergent clusters were observed within C. gachua, C. marulius, C. punctata and C. striata suggesting the potential presence of cryptic species diversity within these lineages. Our findings demonstrate that DNA barcoding is a valuable tool for species identification in challenging and under-studied taxonomic groups such as snakeheads, and provides a useful framework for inferring invasion pathway

  19. Calibrating snakehead diversity with DNA barcodes: expanding taxonomic coverage to enable identification of potential and established invasive species.

    Science.gov (United States)

    Serrao, Natasha R; Steinke, Dirk; Hanner, Robert H

    2014-01-01

    Detecting and documenting the occurrence of invasive species outside their native range requires tools to support their identification. This can be challenging for taxa with diverse life stages and/or problematic or unresolved morphological taxonomies. DNA barcoding provides a potent method for identifying invasive species, as it allows for species identification at all life stages, including fragmentary remains. It also provides an efficient interim taxonomic framework for quantifying cryptic genetic diversity by parsing barcode sequences into discontinuous haplogroup clusters (typical of reproductively isolated species) and labelling them with unique alphanumeric identifiers. Snakehead fishes are a diverse group of opportunistic predators endemic to Asia and Africa that may potentially pose significant threats as aquatic invasive species. At least three snakehead species (Channa argus, C. maculata, and C. marulius) are thought to have entered North America through the aquarium and live-food fish markets, and have established populations, yet their origins remain unclear. The objectives of this study were to assemble a library of DNA barcode sequences derived from expert identified reference specimens in order to determine the identity and aid invasion pathway analysis of the non-indigenous species found in North America using DNA barcodes. Sequences were obtained from 121 tissue samples representing 25 species and combined with public records from GenBank for a total of 36 putative species, which then partitioned into 49 discrete haplogroups. Multiple divergent clusters were observed within C. gachua, C. marulius, C. punctata and C. striata suggesting the potential presence of cryptic species diversity within these lineages. Our findings demonstrate that DNA barcoding is a valuable tool for species identification in challenging and under-studied taxonomic groups such as snakeheads, and provides a useful framework for inferring invasion pathway analysis.

  20. Comparative evaluation of the performance of the Abbott RealTime HIV-1 assay for measurement of HIV-1 plasma viral load on genetically diverse samples from Greece

    Directory of Open Access Journals (Sweden)

    Paraskevis Dimitrios

    2011-01-01

    Full Text Available Abstract Background HIV-1 is characterized by increased genetic heterogeneity which tends to hinder the reliability of detection and accuracy of HIV-1 RNA quantitation assays. Methods In this study, the Abbott RealTime HIV-1 (Abbott RealTime assay was compared to the Roche Cobas TaqMan HIV-1 (Cobas TaqMan and the Siemens Versant HIV-1 RNA 3.0 (bDNA 3.0 assays, using clinical samples of various viral load levels and subtypes from Greece, where the recent epidemiology of HIV-1 infection has been characterized by increasing genetic diversity and a marked increase in subtype A genetic strains among newly diagnosed infections. Results A high correlation was observed between the quantitative results obtained by the Abbott RealTime and the Cobas TaqMan assays. Viral load values quantified by the Abbott RealTime were on average lower than those obtained by the Cobas TaqMan, with a mean (SD difference of -0.206 (0.298 log10 copies/ml. The mean differences according to HIV-1 subtypes between the two techniques for samples of subtype A, B, and non-A/non-B were 0.089, -0.262, and -0.298 log10 copies/ml, respectively. Overall, differences were less than 0.5 log10 for 85% of the samples, and >1 log10 in only one subtype B sample. Similarly, Abbott RealTime and bDNA 3.0 assays yielded a very good correlation of quantitative results, whereas viral load values assessed by the Abbott RealTime were on average higher (mean (SD difference: 0.160 (0.287 log10 copies/ml. The mean differences according to HIV-1 subtypes between the two techniques for subtype A, B and non-A/non-B samples were 0.438, 0.105 and 0.191 log10 copies/ml, respectively. Overall, the majority of samples (86% differed by less than 0.5 log10, while none of the samples showed a deviation of more than 1.0 log10. Conclusions In an area of changing HIV-1 subtype pattern, the Abbott RealTime assay showed a high correlation and good agreement of results when compared both to the Cobas TaqMan and bDNA 3

  1. Rover waste assay system

    Energy Technology Data Exchange (ETDEWEB)

    Akers, D.W.; Stoots, C.M.; Kraft, N.C.; Marts, D.J. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    1997-11-01

    The Rover Waste Assay System (RWAS) is a nondestructive assay system designed for the rapid assay of highly-enriched {sup 235}U contaminated piping, tank sections, and debris from the Rover nuclear rocket fuel processing facility at the Idaho Chemical Processing Plant. A scanning system translates a NaI(Tl) detector/collimator system over the structural components where both relative and calibrated measurements for {sup 137}Cs are made. Uranium-235 concentrations are in operation and is sufficiently automated that most functions are performed by the computer system. These functions include system calibration, problem identification, collimator control, data analysis, and reporting. Calibration of the system was done through a combination of measurements on calibration standards and benchmarked modeling. A description of the system is presented along with the methods and uncertainties associated with the calibration and analysis of the system for components from the Rover facility. 4 refs., 2 figs., 4 tabs.

  2. Assay methods for U-238, Th-232, and Pb-210 in lead and calibration of Bi-210 bremsstrahlung emission from lead

    CERN Document Server

    Orrell, John L; Arnquist, Isaac J; Eggemeyer, Tere A; Glasgow, Brian D; Hoppe, Eric W; Keillor, Martin E; Morley, Shannon M; Myers, Allan W; Overman, Cory T; Shaff, Sarah M; Thommasson, Kimbrelle S

    2015-01-01

    Assay methods for measuring 238U, 232Th, and 210Pb concentrations in refined lead are presented. The 238U and 232Th concentrations are determined using isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) after anion exchange column separation of dissolved lead samples. The 210Pb concentration is inferred through {\\alpha}-spectroscopy of a daughter isotope, 210Po, after chemical precipitation separation on dissolved lead samples. Subsequent to the 210Po {\\alpha}-spectroscopy assay, a method for evaluating 210Pb concentrations in solid lead samples was developed via measurement of bremsstrahlung radiation from \\b{eta}-decay of a daughter isotope, 210Bi, by employing a 14-crystal array of high purity germanium (HPGe) detectors. Ten sources of refined lead were assayed. The 238U concentrations were <34 microBq/kg and the 232Th concentrations ranged <0.6-15 microBq/kg, as determined by the ICP-MS assay method. The 210Pb concentrations ranged from ~0.1-75 Bq/kg, as inferred by the 210Po ...

  3. A lack of premature termination codon read-through efficacy of PTC124 (Ataluren in a diverse array of reporter assays.

    Directory of Open Access Journals (Sweden)

    Stuart P McElroy

    Full Text Available The drug molecule PTC124 (Ataluren has been described as a read-through agent, capable of suppressing premature termination codons (PTCs and restoring functional protein production from genes disrupted by nonsense mutations. Following the discovery of PTC124 there was some controversy regarding its mechanism of action with two reports attributing its activity to an off-target effect on the Firefly luciferase (FLuc reporter used in the development of the molecule. Despite questions remaining as to its mechanism of action, development of PTC124 continued into the clinic and it is being actively pursued as a potential nonsense mutation therapy. To thoroughly test the ability of PTC124 to read through nonsense mutations, we conducted a detailed assessment comparing the efficacy of PTC124 with the classical aminoglycoside antibiotic read-through agent geneticin (G418 across a diverse range of in vitro reporter assays. We can confirm the off-target FLuc activity of PTC124 but found that, while G418 exhibits varying activity in every read-through assay, there is no evidence of activity for PTC124.

  4. Calibration of the γ-H2AX DNA double strand break focus assay for internal radiation exposure of blood lymphocytes.

    Science.gov (United States)

    Eberlein, Uta; Peper, Michel; Fernández, Maria; Lassmann, Michael; Scherthan, Harry

    2015-01-01

    DNA double strand break (DSB) formation induced by ionizing radiation exposure is indicated by the DSB biomarkers γ-H2AX and 53BP1. Knowledge about DSB foci formation in-vitro after internal irradiation of whole blood samples with radionuclides in solution will help us to gain detailed insights about dose-response relationships in patients after molecular radiotherapy (MRT). Therefore, we studied the induction of radiation-induced co-localizing γ-H2AX and 53BP1 foci as surrogate markers for DSBs in-vitro, and correlated the obtained foci per cell values with the in-vitro absorbed doses to the blood for the two most frequently used radionuclides in MRT (I-131 and Lu-177). This approach led to an in-vitro calibration curve. Overall, 55 blood samples of three healthy volunteers were analyzed. For each experiment several vials containing a mixture of whole blood and radioactive solutions with different concentrations of isotonic NaCl-diluted radionuclides with known activities were prepared. Leukocytes were recovered by density centrifugation after incubation and constant blending for 1 h at 37°C. After ethanol fixation they were subjected to two-color immunofluorescence staining and the average frequencies of the co-localizing γ-H2AX and 53BP1 foci/nucleus were determined using a fluorescence microscope equipped with a red/green double band pass filter. The exact activity was determined in parallel in each blood sample by calibrated germanium detector measurements. The absorbed dose rates to the blood per nuclear disintegrations occurring in 1 ml of blood were calculated for both isotopes by a Monte Carlo simulation. The measured blood doses in our samples ranged from 6 to 95 mGy. A linear relationship was found between the number of DSB-marking foci/nucleus and the absorbed dose to the blood for both radionuclides studied. There were only minor nuclide-specific intra- and inter-subject deviations.

  5. Calibration of the γ-H2AX DNA double strand break focus assay for internal radiation exposure of blood lymphocytes.

    Directory of Open Access Journals (Sweden)

    Uta Eberlein

    Full Text Available DNA double strand break (DSB formation induced by ionizing radiation exposure is indicated by the DSB biomarkers γ-H2AX and 53BP1. Knowledge about DSB foci formation in-vitro after internal irradiation of whole blood samples with radionuclides in solution will help us to gain detailed insights about dose-response relationships in patients after molecular radiotherapy (MRT. Therefore, we studied the induction of radiation-induced co-localizing γ-H2AX and 53BP1 foci as surrogate markers for DSBs in-vitro, and correlated the obtained foci per cell values with the in-vitro absorbed doses to the blood for the two most frequently used radionuclides in MRT (I-131 and Lu-177. This approach led to an in-vitro calibration curve. Overall, 55 blood samples of three healthy volunteers were analyzed. For each experiment several vials containing a mixture of whole blood and radioactive solutions with different concentrations of isotonic NaCl-diluted radionuclides with known activities were prepared. Leukocytes were recovered by density centrifugation after incubation and constant blending for 1 h at 37°C. After ethanol fixation they were subjected to two-color immunofluorescence staining and the average frequencies of the co-localizing γ-H2AX and 53BP1 foci/nucleus were determined using a fluorescence microscope equipped with a red/green double band pass filter. The exact activity was determined in parallel in each blood sample by calibrated germanium detector measurements. The absorbed dose rates to the blood per nuclear disintegrations occurring in 1 ml of blood were calculated for both isotopes by a Monte Carlo simulation. The measured blood doses in our samples ranged from 6 to 95 mGy. A linear relationship was found between the number of DSB-marking foci/nucleus and the absorbed dose to the blood for both radionuclides studied. There were only minor nuclide-specific intra- and inter-subject deviations.

  6. Calibration uncertainty

    DEFF Research Database (Denmark)

    Heydorn, Kaj; Anglov, Thomas

    2002-01-01

    Methods recommended by the International Standardization Organisation and Eurachem are not satisfactory for the correct estimation of calibration uncertainty. A novel approach is introduced and tested on actual calibration data for the determination of Pb by ICP-AES. The improved calibration unce...

  7. Occurrence and genetic diversity of Arcobacter spp. in a spinach-processing plant and evaluation of two Arcobacter-specific quantitative PCR assays.

    Science.gov (United States)

    Hausdorf, Lena; Neumann, Maria; Bergmann, Ingo; Sobiella, Kerstin; Mundt, Kerstin; Fröhling, Antje; Schlüter, Oliver; Klocke, Michael

    2013-06-01

    Some species of the genus Arcobacter are considered to be emerging food pathogens. With respect to recent vegetable-borne outbreaks, the aim of this work was to investigate the occurrence and diversity of Arcobacter within the production chain of a spinach-processing plant by a combination of cultivation and molecular methods. Samples including spinach, water, and surface biofilm were taken over a period of three years from the entire processing line. Ten 16S rRNA (rrs) gene clone libraries were constructed and analysed using amplified rRNA gene restriction analysis (ARDRA). Approximately 1200 clones were studied that resulted in 44 operational taxonomic units (OTUs). Sequences with high similarities to Arcobacter cryaerophilus (13% of clones, 3 OTUs), A. ellisii (4%, 6 OTUs), A. suis (15%, 3 OTUs), and the type strain of A. nitrofigilis (1%, 7 OTUs) were identified. This represents the first report of the detection of the recently described species A. ellisii, A. suis and, in addition, A. venerupis from alternative habitats. A total of 67% of the clones (22 OTUs) could not be assigned to a genus, which indicated the presence of uncharacterised Arcobacter species. For the cultivation-independent detection of Arcobacter, two genus-specific quantitative PCR (qPCR) assays were developed and tested on 15 Arcobacter species. When these assays were applied to samples from the spinach-processing plant, they showed positive results for up to 35% of the samples and supported the conclusion that there is a considerable risk for the transfer of pathogenic Arcobacter species on vegetables, which was also verified by a cultivation approach.

  8. Interferon Gamma Release Assay versus Tuberculin Skin Testing among Healthcare Workers of Highly Diverse Origin in a Moderate Tuberculosis Burden Country.

    Science.gov (United States)

    Al Hajoj, Sahal; Varghese, Bright; Datijan, Alria; Shoukri, Mohammed; Alzahrani, Ali; Alkhenizan, Abdallah; AlSaif, Abdulaziz; Althawadi, Sahar; Fernandez, Grace; Alrajhi, Abdulrahman

    2016-01-01

    Health care workers (HCW's) are always at an increased risk of contracting tuberculosis (TB) infection. In Saudi Arabia, Interferon Gamma Release Assay (IGRA) has not been evaluated as a screening tool for latent TB infection (LTBI) among HCW's considering their high demographic diversity. During February 2012 to January 2015 a cross sectional study has been conducted in a tertiary care center with maximum demographically diverse staff population in the capital city-Riyadh. After a short interview and consenting, all the candidates were subjected to tuberculin skin test (TST) and QuantiFERON TB gold In-tube test (QFT). A logistic regression analysis was carried out for establishing the associations between putative risk factors and the diagnostic tests. The candidates were classified according to geographical origin and a detailed analysis was conducted on the impact of their origin towards the results of TST and QFT. Of the 1595 candidates enrolled, 90.6% were BCG vaccinated, female (67.9%) and mainly nurses (53.2%). Candidates with high risk of suspected or confirmed TB patient exposure were 56.1% and 76.5% of them had origin were associated with TST positivity while Occupational TB exposure and geographical origin of the candidates were associated with QFT positivity. A regular follow up on recently TST converted candidates showed no progression to active TB. The putative factors associated with the discordance were origin of the candidate (p value Origin of the candidates has strong association with the results of TST and QFT. The discordant results particularly TST negative and QFT positive needs more detailed analysis.

  9. Characterization of Genetic Diversity of Bacillus anthracis in France by Using High-Resolution Melting Assays and Multilocus Variable-Number Tandem-Repeat Analysis ▿ †

    Science.gov (United States)

    Derzelle, S.; Laroche, S.; Le Flèche, P.; Hauck, Y.; Thierry, S.; Vergnaud, G.; Madani, N.

    2011-01-01

    Using high-resolution melting (HRM) analysis, we developed a cost-effective method to genotype a set of 13 phylogenetically informative single-nucleotide polymorphisms (SNPs) within the genome of Bacillus anthracis. SNP discrimination assays were performed in monoplex or duplex and applied to 100 B. anthracis isolates collected in France from 1953 to 2009 and a few reference strains. HRM provided a reliable and cheap alternative to subtype B. anthracis into one of the 12 major sublineages or subgroups. All strains could be correctly positioned on the canonical SNP (canSNP) phylogenetic tree, except the divergent Pasteur vaccine strain ATCC 4229. We detected the cooccurrence of three canSNP subgroups in France. The dominant B.Br.CNEVA sublineage was found to be prevalent in the Alps, the Pyrenees, the Auvergne region, and the Saône-et-Loire department. Strains affiliated with the A.Br.008/009 subgroup were observed throughout most of the country. The minor A.Br.001/002 subgroup was restricted to northeastern France. Multiple-locus variable-number tandem-repeat analysis using 24 markers further resolved French strains into 60 unique profiles and identified some regional patterns. Diversity found within the A.Br.008/009 and B.Br.CNEVA subgroups suggests that these represent old, ecologically established clades in France. Phylogenetic relationships with strains from other parts of the world are discussed. PMID:21998431

  10. Colorimetric protein assay techniques.

    Science.gov (United States)

    Sapan, C V; Lundblad, R L; Price, N C

    1999-04-01

    There has been an increase in the number of colorimetric assay techniques for the determination of protein concentration over the past 20 years. This has resulted in a perceived increase in sensitivity and accuracy with the advent of new techniques. The present review considers these advances with emphasis on the potential use of such technologies in the assay of biopharmaceuticals. The techniques reviewed include Coomassie Blue G-250 dye binding (the Bradford assay), the Lowry assay, the bicinchoninic acid assay and the biuret assay. It is shown that each assay has advantages and disadvantages relative to sensitivity, ease of performance, acceptance in the literature, accuracy and reproducibility/coefficient of variation/laboratory-to-laboratory variation. A comparison of the use of several assays with the same sample population is presented. It is suggested that the most critical issue in the use of a chromogenic protein assay for the characterization of a biopharmaceutical is the selection of a standard for the calibration of the assay; it is crucial that the standard be representative of the sample. If it is not possible to match the standard with the sample from the perspective of protein composition, then it is preferable to use an assay that is not sensitive to the composition of the protein such as a micro-Kjeldahl technique, quantitative amino acid analysis or the biuret assay. In a complex mixture it might be inappropriate to focus on a general method of protein determination and much more informative to use specific methods relating to the protein(s) of particular interest, using either specific assays or antibody-based methods. The key point is that whatever method is adopted as the 'gold standard' for a given protein, this method needs to be used routinely for calibration.

  11. Incidence in diverse pig populations of an IGF2 mutation with potential influence on meat quality and quantity: An assay based on real time PCR (RT-PCR).

    Science.gov (United States)

    Carrodeguas, José Alberto; Burgos, Carmen; Moreno, Carlos; Sánchez, Ana Cristina; Ventanas, Sonia; Tarrafeta, Luis; Barcelona, José Antonio; López, Maria Otilia; Oria, Rosa; López-Buesa, Pascual

    2005-11-01

    IGF2, insulin-like growth factor 2, is implicated in myogenesis and lean meat content. A mutation in a single base (A for G substitution) of the gene for IGF2 (position 3072 in intron 3) has been recently described as the cause of a major QTL effect on muscle growth in pigs [Van Laere, A. S, Nguyen, M., Braunschweig, M., Nezer, C., Collete, C., & Moreau, L. et al. (2003). Nature, 425, 832-836]. We describe here a rapid assay based on real time PCR (RT-PCR) to detect this mutation. We have evaluated the incidence of the mutation in commercial pig crosses, in three populations of purebred Iberian or Iberian×Duroc crosses, and in cured meat products and wild boars. The incidence of the mutation varies among these groups. Penetrance of the A mutation is about 80% in the commercial population. Purebred Iberian pigs were all homozygous G/G whereas crosses of Iberian pigs were heterozygous (90%) or homozygous A/A (10%). The implications of this gene for the selection of Iberian pigs are discussed.

  12. Utility of specimens positive for Neisseria gonorrhoeae by the Aptima Combo 2 assay for assessment of strain diversity and antibiotic resistance.

    Science.gov (United States)

    Pabbaraju, Kanti; Wong, Sallene; Song, Joanna J; Singh, Ameeta E; Read, Ron; Drews, Steven J

    2013-12-01

    In our jurisdiction, the Aptima Combo 2 assay (Gen-Probe, Inc.) is used to detect Neisseria gonorrhoeae from specimens collected at clinics for sexually transmitted infections (STI) and from select community patients. In addition, swabs are also collected for N. gonorrhoeae culture, susceptibility testing, and sequence typing (ST). Since only a small proportion of samples from provincial cases undergo culture, the available trends in antimicrobial susceptibility and predominant strain types may not be representative of all N. gonorrhoeae infections. Due to the limitations facing the use of N. gonorrhoeae culture to understand these trends in the general community, we performed a molecular analysis for markers of cephalosporin resistance and ST determination by using nucleic acid extracts of specimens sent for Aptima testing. Thirty-four samples submitted for both Aptima testing and N. gonorrhoeae culture from the same anatomic location (within 24 h) were included in the study. Sequence type was determined based on the sequence of the por and tbpB genes, and amino acid changes in the PBP 2 protein, encoded by the penA gene, were considered representative for the assessment of antimicrobial susceptibility. Sequence identity of 100% was observed between the sequences obtained from Aptima-analyzed samples and culture samples. Sequencing results showed an association between decreased susceptibility to extended-spectrum cephalosporins (ESC(ds)), tbp allele 110, ST 1407, and amino acid changes (G545S, I312M, and V316T) in the PBP 2 protein. Our data, generated based on a few representative genes, suggest that gonococcal samples positive by Aptima testing can be used to determine single nucleotide polymorphisms associated with ESC(ds) and the sequence type based on molecular strain typing. Confirmation of these findings may obviate the need for gonorrhea culture in the future.

  13. Reduced Ambiguity Calibration for LOFAR

    CERN Document Server

    Yatawatta, Sarod

    2012-01-01

    Interferometric calibration always yields non unique solutions. It is therefore essential to remove these ambiguities before the solutions could be used in any further modeling of the sky, the instrument or propagation effects such as the ionosphere. We present a method for LOFAR calibration which does not yield a unitary ambiguity, especially under ionospheric distortions. We also present exact ambiguities we get in our solutions, in closed form. Casting this as an optimization problem, we also present conditions for this approach to work. The proposed method enables us to use the solutions obtained via calibration for further modeling of instrumental and propagation effects. We provide extensive simulation results on the performance of our method. Moreover, we also give cases where due to degeneracy, this method fails to perform as expected and in such cases, we suggest exploiting diversity in time, space and frequency.

  14. Traceable Pyrgeometer Calibrations

    Energy Technology Data Exchange (ETDEWEB)

    Dooraghi, Mike; Kutchenreiter, Mark; Reda, Ibrahim; Habte, Aron; Sengupta, Manajit; Andreas, Afshin; Newman, Martina

    2016-05-02

    This poster presents the development, implementation, and operation of the Broadband Outdoor Radiometer Calibrations (BORCAL) Longwave (LW) system at the Southern Great Plains Radiometric Calibration Facility for the calibration of pyrgeometers that provide traceability to the World Infrared Standard Group.

  15. Calibration of sound calibrators: an overview

    Science.gov (United States)

    Milhomem, T. A. B.; Soares, Z. M. D.

    2016-07-01

    This paper presents an overview of calibration of sound calibrators. Initially, traditional calibration methods are presented. Following, the international standard IEC 60942 is discussed emphasizing parameters, target measurement uncertainty and criteria for conformance to the requirements of the standard. Last, Regional Metrology Organizations comparisons are summarized.

  16. Enzyme assays.

    Science.gov (United States)

    Reymond, Jean-Louis; Fluxà, Viviana S; Maillard, Noélie

    2009-01-07

    Enzyme assays are analytical tools to visualize enzyme activities. In recent years a large variety of enzyme assays have been developed to assist the discovery and optimization of industrial enzymes, in particular for "white biotechnology" where selective enzymes are used with great success for economically viable, mild and environmentally benign production processes. The present article highlights the aspects of fluorogenic and chromogenic substrates, sensors, and enzyme fingerprinting, which are our particular areas of interest.

  17. Trinocular Calibration Method Based on Binocular Calibration

    Directory of Open Access Journals (Sweden)

    CAO Dan-Dan

    2012-10-01

    Full Text Available In order to solve the self-occlusion problem in plane-based multi-camera calibration system and expand the measurement range, a tri-camera vision system based on binocular calibration is proposed. The three cameras are grouped into two pairs, while the public camera is taken as the reference to build the global coordinate. By calibration of the measured absolute distance and the true absolute distance, global calibration is realized. The MRE (mean relative error of the global calibration of the two camera pairs in the experiments can be as low as 0.277% and 0.328% respectively. Experiment results show that this method is feasible, simple and effective, and has high precision.

  18. Standard guide for making quality nondestructive assay measurements

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This guide is a compendium of Quality Measurement Practices for performing measurements of radioactive material using nondestructive assay (NDA) instruments. The primary purpose of the guide is to assist users in arriving at quality NDA results, that is, results that satisfy the end user’s needs. This is accomplished by providing an acceptable and uniform basis for the collection, analysis, comparison, and application of data. The recommendations are not compulsory or prerequisites to achieving quality NDA measurements, but are considered contributory in most areas. 1.2 This guide applies to the use of NDA instrumentation for the measurement of nuclear materials by the observation of spontaneous or stimulated nuclear radiations, including photons, neutrons, or the flow of heat. Recommended calibration, operating, and assurance methods represent guiding principles based on current NDA technology. The diversity of industry-wide nuclear materials measurement applications and instrumentation precludes disc...

  19. Syringe calibration factors and volume correction factors for the NPL secondary standard radionuclide calibrator

    CERN Document Server

    Tyler, D K

    2002-01-01

    The activity assay of a radiopharmaceutical administration to a patient is normally achieved via the use of a radionuclide calibrator. Because of the different geometries and elemental compositions between plastic syringes and glass vials, the calibration factors for syringes may well be significantly different from those for the glass containers. The magnitude of these differences depends on the energies of the emitted photons. For some radionuclides variations have been observed of 70 %, it is therefore important to recalibrate for syringes or use syringe calibration factors. Calibration factors and volume correction factors have been derived for the NPL secondary standard radionuclide calibrator, for a variety of commonly used syringes and needles, for the most commonly used medical radionuclide.

  20. The calibration of PIXIE

    Science.gov (United States)

    Fixsen, D. J.; Chuss, D. T.; Kogut, Alan; Mirel, Paul; Wollack, E. J.

    2016-07-01

    The FIRAS instrument demonstrated the use of an external calibrator to compare the sky to an instrumented blackbody. The PIXIE calibrator is improved from -35 dB to -65 dB. Another significant improvement is the ability to insert the calibrator into either input of the FTS. This allows detection and correction of additional errors, reduces the effective calibration noise by a factor of 2, eliminates an entire class of systematics and allows continuous observations. This paper presents the design and use of the PIXIE calibrator.

  1. Distributed Radio Interferometric Calibration

    CERN Document Server

    Yatawatta, Sarod

    2015-01-01

    Increasing data volumes delivered by a new generation of radio interferometers require computationally efficient and robust calibration algorithms. In this paper, we propose distributed calibration as a way of improving both computational cost as well as robustness in calibration. We exploit the data parallelism across frequency that is inherent in radio astronomical observations that are recorded as multiple channels at different frequencies. Moreover, we also exploit the smoothness of the variation of calibration parameters across frequency. Data parallelism enables us to distribute the computing load across a network of compute agents. Smoothness in frequency enables us reformulate calibration as a consensus optimization problem. With this formulation, we enable flow of information between compute agents calibrating data at different frequencies, without actually passing the data, and thereby improving robustness. We present simulation results to show the feasibility as well as the advantages of distribute...

  2. The Science of Calibration

    Science.gov (United States)

    Kent, S. M.

    2016-05-01

    This paper presents a broad overview of the many issues involved in calibrating astronomical data, covering the full electromagnetic spectrum from radio waves to gamma rays, and considering both ground-based and space-based missions. These issues include the science drivers for absolute and relative calibration, the physics behind calibration and the mechanisms used to transfer it from the laboratory to an astronomical source, the need for networks of calibrated astronomical standards, and some of the challenges faced by large surveys and missions.

  3. OLI Radiometric Calibration

    Science.gov (United States)

    Markham, Brian; Morfitt, Ron; Kvaran, Geir; Biggar, Stuart; Leisso, Nathan; Czapla-Myers, Jeff

    2011-01-01

    Goals: (1) Present an overview of the pre-launch radiance, reflectance & uniformity calibration of the Operational Land Imager (OLI) (1a) Transfer to orbit/heliostat (1b) Linearity (2) Discuss on-orbit plans for radiance, reflectance and uniformity calibration of the OLI

  4. Lidar to lidar calibration

    DEFF Research Database (Denmark)

    Fernandez Garcia, Sergio; Villanueva, Héctor

    This report presents the result of the lidar to lidar calibration performed for ground-based lidar. Calibration is here understood as the establishment of a relation between the reference lidar wind speed measurements with measurement uncertainties provided by measurement standard and correspondi...

  5. Sandia WIPP calibration traceability

    Energy Technology Data Exchange (ETDEWEB)

    Schuhen, M.D. [Sandia National Labs., Albuquerque, NM (United States); Dean, T.A. [RE/SPEC, Inc., Albuquerque, NM (United States)

    1996-05-01

    This report summarizes the work performed to establish calibration traceability for the instrumentation used by Sandia National Laboratories at the Waste Isolation Pilot Plant (WIPP) during testing from 1980-1985. Identifying the calibration traceability is an important part of establishing a pedigree for the data and is part of the qualification of existing data. In general, the requirement states that the calibration of Measuring and Test equipment must have a valid relationship to nationally recognized standards or the basis for the calibration must be documented. Sandia recognized that just establishing calibration traceability would not necessarily mean that all QA requirements were met during the certification of test instrumentation. To address this concern, the assessment was expanded to include various activities.

  6. WFPC2 Polarization Calibration

    Science.gov (United States)

    Biretta, J.; McMaster, M.

    1997-12-01

    We derive a detailed calibration for WFPC2 polarization data which is accurate to about 1.5%. We begin by computing polarizer flats, and show how they are applied to data. A physical model for the polarization effects of the WFPC2 optics is then created using Mueller matricies. This model includes corrections for the instrumental polarization (diattenuation and phase retardance) of the pick-off mirror, as well as the high cross-polarization transmission of the polarizer filter. We compare this model against the on-orbit observations of polarization calibrators, and show it predicts relative counts in the different polarizer/aperture settings to 1.5% RMS accuracy. We then show how this model can be used to calibrate GO data, and present two WWW tools which allow observers to easily calibrate their data. Detailed examples are given illustrationg the calibration and display of WFPC2 polarization data. In closing we describe future plans and possible improvements.

  7. Segment Based Camera Calibration

    Institute of Scientific and Technical Information of China (English)

    马颂德; 魏国庆; 等

    1993-01-01

    The basic idea of calibrating a camera system in previous approaches is to determine camera parmeters by using a set of known 3D points as calibration reference.In this paper,we present a method of camera calibration in whih camera parameters are determined by a set of 3D lines.A set of constraints is derived on camea parameters in terms of perspective line mapping.Form these constraints,the same perspective transformation matrix as that for point mapping can be computed linearly.The minimum number of calibration lines is 6.This result generalizes that of Liu,Huang and Faugeras[12] for camera location determination in which at least 8 line correspondences are required for linear computation of camera location.Since line segments in an image can be located easily and more accurately than points,the use of lines as calibration reference tends to ease the computation in inage preprocessing and to improve calibration accuracy.Experimental results on the calibration along with stereo reconstruction are reported.

  8. Real-Time TaqMan PCR Assay for the Detection of Heat-Labile and Heat-Stable Enterotoxin Genes in a Geographically Diverse Collection of Enterotoxigenic Escherichia coli Strains and Stool Specimens.

    Science.gov (United States)

    Pattabiraman, Vaishnavi; Parsons, Michele B; Bopp, Cheryl A

    2016-04-01

    Enterotoxigenic Escherichia coli (ETEC) are an important cause of diarrhea in children under the age of 5 years in developing countries and are the leading bacterial agent of traveler's diarrhea in persons traveling to these countries. ETEC strains secrete heat-labile (LT) and/or heat-stable (ST) enterotoxins that induce diarrhea by causing water and electrolyte imbalance. We describe the validation of a real-time TaqMan PCR (RT-PCR) assay to detect LT, ST1a, and ST1b enterotoxin genes in E. coli strains and in stool specimens. We validated LT/ST1b duplex and ST1a single-plex RT-PCR assay using a conventional PCR assay as a gold standard with 188 ETEC strains and 42 non-ETEC strains. We validated LT/ST1b duplex and ST1a single-plex RT-PCR assay in stool specimens (n = 106) using traditional culture as the gold standard. RT- PCR assay sensitivities for LT, ST1a, and ST1b detection in strains were 100%, 100%, and 98%; specificities were 95%, 98%, and 99%, and Pearson correlation coefficient r was 0.9954 between RT-PCR assay and the gold standard. In stool specimens, RT-PCR assay sensitivities for LT, ST1a, and ST1b detection were 97%, 100%, and 97%; and specificities were 99%, 94%, and 97%. Pearson correlation coefficient r was 0.9975 between RT-PCR results in stool specimens and the gold standard. Limits of detection of LT, ST1a, and ST1b by RT-PCR assay were 0.1 to1.0 pg/μL and by conventional PCR assay were 100 to1000 pg/μL. The accuracy, rapidity and sensitivity of this RT-PCR assay is promising for ETEC detection in public health/clinical laboratories and for laboratories in need of an independent method to confirm results of other culture independent diagnostic tests.

  9. Lidar to lidar calibration

    DEFF Research Database (Denmark)

    Georgieva Yankova, Ginka; Courtney, Michael

    This report presents the result of the lidar to lidar calibration performed for ground-based lidar. Calibration is here understood as the establishment of a relation between the reference lidar wind speed measurements with measurement uncertainties provided by measurement standard and corresponding...... lidar wind speed indications with associated measurement uncertainties. The lidar calibration concerns the 10 minute mean wind speed measurements. The comparison of the lidar measurements of the wind direction with that from the reference lidar measurements are given for information only....

  10. Site Calibration report

    DEFF Research Database (Denmark)

    Gómez Arranz, Paula; Vesth, Allan

    This report describes the site calibration carried out at Østerild, during a given period. The site calibration was performed with two Windcube WLS7 (v1) lidars at ten measurements heights. The lidar is not a sensor approved by the current version of the IEC 61400-12-1 [1] and therefore the site...... calibration with lidars does not comply with the standard. However, the measurements are carried out following the guidelines of IEC 61400-12-1 where possible, but with some deviations presented in the following chapters....

  11. Impact of calibration fitting models on the clinical value of chromogranin A

    OpenAIRE

    Ferraro, Simona; Marano, Giuseppe; Ciardi, Laura; Vendramin, Chiara; Bongo, Angelo S.; Bellomo, Giorgio; Boracchi, Patrizia; Biganzoli, Elia M.

    2009-01-01

    Background: The clinical relevance of chromogranin A (CgA) concentrations depends on the analytical performance of the assay. The goal of the present study was to define the clinical involvements in CgA calibration models by evaluating the confidence intervals (CIs) for values from patients who were undergoing monitoring for disease. Methods: Thirty calibration curves for the CgA assay [immunoradiometric assay (IRMA), (CIS-BIO)] were built using linear regression (LR), and four-parameter log...

  12. Calibration Fixture For Anemometer Probes

    Science.gov (United States)

    Lewis, Charles R.; Nagel, Robert T.

    1993-01-01

    Fixture facilitates calibration of three-dimensional sideflow thermal anemometer probes. With fixture, probe oriented at number of angles throughout its design range. Readings calibrated as function of orientation in airflow. Calibration repeatable and verifiable.

  13. Input calibration for negative originals

    Science.gov (United States)

    Tuijn, Chris

    1995-04-01

    One of the major challenges in the prepress environment consists of controlling the electronic color reproduction process such that a perfect match of any original can be realized. Whether this goal can be reached depends on many factors such as the dynamic range of the input device (scanner, camera), the color gamut of the output device (dye sublimation printer, ink-jet printer, offset), the color management software etc. The characterization of the color behavior of the peripheral devices is therefore very important. Photographs and positive transparents reflect the original scene pretty well; for negative originals, however, there is no obvious link to either the original scene or a particular print of the negative under consideration. In this paper, we establish a method to scan negatives and to convert the scanned data to a calibrated RGB space, which is known colorimetrically. This method is based on the reconstruction of the original exposure conditions (i.e., original scene) which generated the negative. Since the characteristics of negative film are quite diverse, a special calibration is required for each combination of scanner and film type.

  14. SPOTS Calibration Example

    Directory of Open Access Journals (Sweden)

    Patterson E.

    2010-06-01

    Full Text Available The results are presented using the procedure outlined by the Standardisation Project for Optical Techniques of Strain measurement to calibrate a digital image correlation system. The process involves comparing the experimental data obtained with the optical measurement system to the theoretical values for a specially designed specimen. The standard states the criteria which must be met in order to achieve successful calibration, in addition to quantifying the measurement uncertainty in the system. The system was evaluated at three different displacement load levels, generating strain ranges from 289 µstrain to 2110 µstrain. At the 289 µstrain range, the calibration uncertainty was found to be 14.1 µstrain, and at the 2110 µstrain range it was found to be 28.9 µstrain. This calibration procedure was performed without painting a speckle pattern on the surface of the metal. Instead, the specimen surface was prepared using different grades of grit paper to produce the desired texture.

  15. Air Data Calibration Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This facility is for low altitude subsonic altimeter system calibrations of air vehicles. Mission is a direct support of the AFFTC mission. Postflight data merge is...

  16. Traceable Pyrgeometer Calibrations

    Energy Technology Data Exchange (ETDEWEB)

    Dooraghi, Mike; Kutchenreiter, Mark; Reda, Ibrahim; Habte, Aron; Sengupta, Manajit; Andreas, Afshin; Newman, Martina; Webb, Craig

    2016-05-02

    This presentation provides a high-level overview of the progress on the Broadband Outdoor Radiometer Calibrations for all shortwave and longwave radiometers that are deployed by the Atmospheric Radiation Measurement program.

  17. SRHA calibration curve

    Data.gov (United States)

    U.S. Environmental Protection Agency — an UV calibration curve for SRHA quantitation This dataset is associated with the following publication: Chang, X., and D. Bouchard. Surfactant-Wrapped Multiwalled...

  18. Calibrating nacelle lidars

    DEFF Research Database (Denmark)

    Courtney, Michael

    Nacelle mounted, forward looking wind lidars are beginning to be used to provide reference wind speed measurements for the power performance testing of wind turbines. In such applications, a formal calibration procedure with a corresponding uncertainty assessment will be necessary. This report...... presents four concepts for performing such a nacelle lidar calibration. Of the four methods, two are found to be immediately relevant and are pursued in some detail. The first of these is a line of sight calibration method in which both lines of sight (for a two beam lidar) are individually calibrated...... a representative distribution of radial wind speeds. An alternative method is to place the nacelle lidar on the ground and incline the beams upwards to bisect a mast equipped with reference instrumentation at a known height and range. This method will be easier and faster to implement and execute but the beam...

  19. Calibrating nacelle lidars

    OpenAIRE

    Courtney, Michael

    2013-01-01

    Nacelle mounted, forward looking wind lidars are beginning to be used to provide reference wind speed measurements for the power performance testing of wind turbines. In such applications, a formal calibration procedure with a corresponding uncertainty assessment will be necessary. This report presents four concepts for performing such a nacelle lidar calibration. Of the four methods, two are found to be immediately relevant and are pursued in some detail.The first of these is a line of sight...

  20. TWSTFT Link Calibration Report

    Science.gov (United States)

    2015-09-01

    box calibrator with unknown but constant total delay during a calibration tour Total Delay: The total electrical delay from the antenna phase center...to the UTCp including all the devices/cables that the satellite and clock signals pass through. It numerically equals the sum of all the sub-delays...PTB. To average out the dimnal effects and measurement noise , 5-7 days of continuous measurements is required. 3 Setups at the Lab(k) The setup

  1. Calibrating nacelle lidars

    Energy Technology Data Exchange (ETDEWEB)

    Courtney, M.

    2013-01-15

    Nacelle mounted, forward looking wind lidars are beginning to be used to provide reference wind speed measurements for the power performance testing of wind turbines. In such applications, a formal calibration procedure with a corresponding uncertainty assessment will be necessary. This report presents four concepts for performing such a nacelle lidar calibration. Of the four methods, two are found to be immediately relevant and are pursued in some detail. The first of these is a line of sight calibration method in which both lines of sight (for a two beam lidar) are individually calibrated by accurately aligning the beam to pass close to a reference wind speed sensor. A testing procedure is presented, reporting requirements outlined and the uncertainty of the method analysed. It is seen that the main limitation of the line of sight calibration method is the time required to obtain a representative distribution of radial wind speeds. An alternative method is to place the nacelle lidar on the ground and incline the beams upwards to bisect a mast equipped with reference instrumentation at a known height and range. This method will be easier and faster to implement and execute but the beam inclination introduces extra uncertainties. A procedure for conducting such a calibration is presented and initial indications of the uncertainties given. A discussion of the merits and weaknesses of the two methods is given together with some proposals for the next important steps to be taken in this work. (Author)

  2. Energy calibration via correlation

    CERN Document Server

    Maier, Daniel

    2015-01-01

    The main task of an energy calibration is to find a relation between pulse-height values and the corresponding energies. Doing this for each pulse-height channel individually requires an elaborated input spectrum with an excellent counting statistics and a sophisticated data analysis. This work presents an easy to handle energy calibration process which can operate reliably on calibration measurements with low counting statistics. The method uses a parameter based model for the energy calibration and concludes on the optimal parameters of the model by finding the best correlation between the measured pulse-height spectrum and multiple synthetic pulse-height spectra which are constructed with different sets of calibration parameters. A CdTe-based semiconductor detector and the line emissions of an 241 Am source were used to test the performance of the correlation method in terms of systematic calibration errors for different counting statistics. Up to energies of 60 keV systematic errors were measured to be le...

  3. Calibration Under Uncertainty.

    Energy Technology Data Exchange (ETDEWEB)

    Swiler, Laura Painton; Trucano, Timothy Guy

    2005-03-01

    This report is a white paper summarizing the literature and different approaches to the problem of calibrating computer model parameters in the face of model uncertainty. Model calibration is often formulated as finding the parameters that minimize the squared difference between the model-computed data (the predicted data) and the actual experimental data. This approach does not allow for explicit treatment of uncertainty or error in the model itself: the model is considered the %22true%22 deterministic representation of reality. While this approach does have utility, it is far from an accurate mathematical treatment of the true model calibration problem in which both the computed data and experimental data have error bars. This year, we examined methods to perform calibration accounting for the error in both the computer model and the data, as well as improving our understanding of its meaning for model predictability. We call this approach Calibration under Uncertainty (CUU). This talk presents our current thinking on CUU. We outline some current approaches in the literature, and discuss the Bayesian approach to CUU in detail.

  4. HAWC Timing Calibration

    CERN Document Server

    Huentemeyer, Petra; Dingus, Brenda

    2009-01-01

    The High-Altitude Water Cherenkov (HAWC) Experiment is a second-generation highsensitivity gamma-ray and cosmic-ray detector that builds on the experience and technology of the Milagro observatory. Like Milagro, HAWC utilizes the water Cherenkov technique to measure extensive air showers. Instead of a pond filled with water (as in Milagro) an array of closely packed water tanks is used. The event direction will be reconstructed using the times when the PMTs in each tank are triggered. Therefore, the timing calibration will be crucial for reaching an angular resolution as low as 0.25 degrees.We propose to use a laser calibration system, patterned after the calibration system in Milagro. Like Milagro, the HAWC optical calibration system will use ~1 ns laser light pulses. Unlike Milagro, the PMTs are optically isolated and require their own optical fiber calibration. For HAWC the laser light pulses will be directed through a series of optical fan-outs and fibers to illuminate the PMTs in approximately one half o...

  5. Calibration Systems Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Myers, Tanya L.; Broocks, Bryan T.; Phillips, Mark C.

    2006-02-01

    The Calibration Systems project at Pacific Northwest National Laboratory (PNNL) is aimed towards developing and demonstrating compact Quantum Cascade (QC) laser-based calibration systems for infrared imaging systems. These on-board systems will improve the calibration technology for passive sensors, which enable stand-off detection for the proliferation or use of weapons of mass destruction, by replacing on-board blackbodies with QC laser-based systems. This alternative technology can minimize the impact on instrument size and weight while improving the quality of instruments for a variety of missions. The potential of replacing flight blackbodies is made feasible by the high output, stability, and repeatability of the QC laser spectral radiance.

  6. Ibis ground calibration

    Energy Technology Data Exchange (ETDEWEB)

    Bird, A.J.; Barlow, E.J.; Tikkanen, T. [Southampton Univ., School of Physics and Astronomy (United Kingdom); Bazzano, A.; Del Santo, M.; Ubertini, P. [Istituto di Astrofisica Spaziale e Fisica Cosmica - IASF/CNR, Roma (Italy); Blondel, C.; Laurent, P.; Lebrun, F. [CEA Saclay - Sap, 91 - Gif sur Yvette (France); Di Cocco, G.; Malaguti, E. [Istituto di Astrofisica Spaziale e Fisica-Bologna - IASF/CNR (Italy); Gabriele, M.; La Rosa, G.; Segreto, A. [Istituto di Astrofisica Spaziale e Fisica- IASF/CNR, Palermo (Italy); Quadrini, E. [Istituto di Astrofisica Spaziale e Fisica-Cosmica, EASF/CNR, Milano (Italy); Volkmer, R. [Institut fur Astronomie und Astrophysik, Tubingen (Germany)

    2003-11-01

    We present an overview of results obtained from IBIS ground calibrations. The spectral and spatial characteristics of the detector planes and surrounding passive materials have been determined through a series of calibration campaigns. Measurements of pixel gain, energy resolution, detection uniformity, efficiency and imaging capability are presented. The key results obtained from the ground calibration have been: - optimization of the instrument tunable parameters, - determination of energy linearity for all detection modes, - determination of energy resolution as a function of energy through the range 20 keV - 3 MeV, - demonstration of imaging capability in each mode, - measurement of intrinsic detector non-uniformity and understanding of the effects of passive materials surrounding the detector plane, and - discovery (and closure) of various leakage paths through the passive shielding system.

  7. TARGETLESS CAMERA CALIBRATION

    Directory of Open Access Journals (Sweden)

    L. Barazzetti

    2012-09-01

    Full Text Available In photogrammetry a camera is considered calibrated if its interior orientation parameters are known. These encompass the principal distance, the principal point position and some Additional Parameters used to model possible systematic errors. The current state of the art for automated camera calibration relies on the use of coded targets to accurately determine the image correspondences. This paper presents a new methodology for the efficient and rigorous photogrammetric calibration of digital cameras which does not require any longer the use of targets. A set of images depicting a scene with a good texture are sufficient for the extraction of natural corresponding image points. These are automatically matched with feature-based approaches and robust estimation techniques. The successive photogrammetric bundle adjustment retrieves the unknown camera parameters and their theoretical accuracies. Examples, considerations and comparisons with real data and different case studies are illustrated to show the potentialities of the proposed methodology.

  8. Performance Testing of PCR Assay in Blood Samples for the Diagnosis of Toxoplasmic Encephalitis in AIDS Patients from the French Departments of America and Genetic Diversity of Toxoplasma gondii: A Prospective and Multicentric Study.

    Directory of Open Access Journals (Sweden)

    Daniel Ajzenberg

    2016-06-01

    Full Text Available Toxoplasmic encephalitis in patients with AIDS is a life-threatening disease mostly due to reactivation of Toxoplasma gondii cysts in the brain. The main objective of this study was to evaluate the performance of real-time PCR assay in peripheral blood samples for the diagnosis of toxoplasmic encephalitis in AIDS patients in the French West Indies and Guiana.Adult patients with HIV and suspicion of toxoplasmic encephalitis with start of specific antitoxoplasmic therapy were included in this study during 40 months. The real-time PCR assay targeting the 529 bp repeat region of T. gondii was performed in two different centers for all blood samples. A Neighbor-Joining tree was reconstructed from microsatellite data to examine the relationships between strains from human cases of toxoplasmosis in South America and the Caribbean. A total of 44 cases were validated by a committee of experts, including 36 cases with toxoplasmic encephalitis. The specificity of the PCR assay in blood samples was 100% but the sensitivity was only 25% with moderate agreement between the two centers. Altered level of consciousness and being born in the French West Indies and Guiana were the only two variables that were associated with significantly decreased risk of false negative results with the PCR assay.Our results showed that PCR sensitivity in blood samples increased with severity of toxoplasmic encephalitis in AIDS patients. Geographic origin of patients was likely to influence PCR sensitivity but there was little evidence that it was caused by differences in T. gondii strains.ClinicalTrials.gov NCT00803621.

  9. Iterative Magnetometer Calibration

    Science.gov (United States)

    Sedlak, Joseph

    2006-01-01

    This paper presents an iterative method for three-axis magnetometer (TAM) calibration that makes use of three existing utilities recently incorporated into the attitude ground support system used at NASA's Goddard Space Flight Center. The method combines attitude-independent and attitude-dependent calibration algorithms with a new spinning spacecraft Kalman filter to solve for biases, scale factors, nonorthogonal corrections to the alignment, and the orthogonal sensor alignment. The method is particularly well-suited to spin-stabilized spacecraft, but may also be useful for three-axis stabilized missions given sufficient data to provide observability.

  10. Marine X-band Weather Radar Data Calibration

    DEFF Research Database (Denmark)

    Thorndahl, Søren Liedtke; Rasmussen, Michael R.

    2012-01-01

    Application of weather radar data in urban hydrology is evolving and radar data is now applied for both modelling, analysis, and real time control purposes. In these contexts, it is allimportant that the radar data is well calibrated and adjusted in order to obtain valid quantitative precipitation...... estimates. This paper presents some of the challenges in small marine X-band radar calibration by comparing three calibration procedures for assessing the relationship between radar and rain gauge data. Validation shows similar results for precipitation volumes but more diverse results on peak rain...

  11. Smart Calibration of Excavators

    DEFF Research Database (Denmark)

    Bro, Marie; Døring, Kasper; Ellekilde, Lars-Peter

    2005-01-01

    Excavators dig holes. But where is the bucket? The purpose of this report is to treat four different problems concerning calibrations of position indicators for excavators in operation at concrete construction sites. All four problems are related to the question of how to determine the precise ge...

  12. Calibrating Communication Competencies

    Science.gov (United States)

    Surges Tatum, Donna

    2016-11-01

    The Many-faceted Rasch measurement model is used in the creation of a diagnostic instrument by which communication competencies can be calibrated, the severity of observers/raters can be determined, the ability of speakers measured, and comparisons made between various groups.

  13. Entropic calibration revisited

    Energy Technology Data Exchange (ETDEWEB)

    Brody, Dorje C. [Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom)]. E-mail: d.brody@imperial.ac.uk; Buckley, Ian R.C. [Centre for Quantitative Finance, Imperial College, London SW7 2AZ (United Kingdom); Constantinou, Irene C. [Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom); Meister, Bernhard K. [Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom)

    2005-04-11

    The entropic calibration of the risk-neutral density function is effective in recovering the strike dependence of options, but encounters difficulties in determining the relevant greeks. By use of put-call reversal we apply the entropic method to the time reversed economy, which allows us to obtain the spot price dependence of options and the relevant greeks.

  14. Calibration with Absolute Shrinkage

    DEFF Research Database (Denmark)

    Øjelund, Henrik; Madsen, Henrik; Thyregod, Poul

    2001-01-01

    is suggested to cope with the singular design matrix most often seen in chemometric calibration. Furthermore, the proposed algorithm may be generalized to all convex norms like Sigma/beta (j)/(gamma) where gamma greater than or equal to 1, i.e. a method that continuously varies from ridge regression...

  15. LOFAR facet calibration

    CERN Document Server

    van Weeren, R J; Hardcastle, M J; Shimwell, T W; Rafferty, D A; Sabater, J; Heald, G; Sridhar, S S; Dijkema, T J; Brunetti, G; Brüggen, M; Andrade-Santos, F; Ogrean, G A; Röttgering, H J A; Dawson, W A; Forman, W R; de Gasperin, F; Jones, C; Miley, G K; Rudnick, L; Sarazin, C L; Bonafede, A; Best, P N; Bîrzan, L; Cassano, R; Chyży, K T; Croston, J H; Ensslin, T; Ferrari, C; Hoeft, M; Horellou, C; Jarvis, M J; Kraft, R P; Mevius, M; Intema, H T; Murray, S S; Orrú, E; Pizzo, R; Simionescu, A; Stroe, A; van der Tol, S; White, G J

    2016-01-01

    LOFAR, the Low-Frequency Array, is a powerful new radio telescope operating between 10 and 240 MHz. LOFAR allows detailed sensitive high-resolution studies of the low-frequency radio sky. At the same time LOFAR also provides excellent short baseline coverage to map diffuse extended emission. However, producing high-quality deep images is challenging due to the presence of direction dependent calibration errors, caused by imperfect knowledge of the station beam shapes and the ionosphere. Furthermore, the large data volume and presence of station clock errors present additional difficulties. In this paper we present a new calibration scheme, which we name facet calibration, to obtain deep high-resolution LOFAR High Band Antenna images using the Dutch part of the array. This scheme solves and corrects the direction dependent errors in a number of facets that cover the observed field of view. Facet calibration provides close to thermal noise limited images for a typical 8 hr observing run at $\\sim$ 5arcsec resolu...

  16. Measurement System & Calibration report

    DEFF Research Database (Denmark)

    Kock, Carsten Weber; Vesth, Allan

    This Measurement System & Calibration report is describing DTU’s measurement system installed at a specific wind turbine. A major part of the sensors has been installed by others (see [1]) the rest of the sensors have been installed by DTU. The results of the measurements, described in this report...

  17. NVLAP calibration laboratory program

    Energy Technology Data Exchange (ETDEWEB)

    Cigler, J.L.

    1993-12-31

    This paper presents an overview of the progress up to April 1993 in the development of the Calibration Laboratories Accreditation Program within the framework of the National Voluntary Laboratory Accreditation Program (NVLAP) at the National Institute of Standards and Technology (NIST).

  18. Mercury CEM Calibration

    Energy Technology Data Exchange (ETDEWEB)

    John F. Schabron; Joseph F. Rovani; Susan S. Sorini

    2007-03-31

    The Clean Air Mercury Rule (CAMR) which was published in the Federal Register on May 18, 2005, requires that calibration of mercury continuous emissions monitors (CEMs) be performed with NIST-traceable standards. Western Research Institute (WRI) is working closely with the Electric Power Research Institute (EPRI), the National Institute of Standards and Technology (NIST), and the Environmental Protection Agency (EPA) to facilitate the development of the experimental criteria for a NIST traceability protocol for dynamic elemental mercury vapor generators. The traceability protocol will be written by EPA. Traceability will be based on the actual analysis of the output of each calibration unit at several concentration levels ranging from about 2-40 ug/m{sup 3}, and this analysis will be directly traceable to analyses by NIST using isotope dilution inductively coupled plasma/mass spectrometry (ID ICP/MS) through a chain of analyses linking the calibration unit in the power plant to the NIST ID ICP/MS. Prior to this project, NIST did not provide a recommended mercury vapor pressure equation or list mercury vapor pressure in its vapor pressure database. The NIST Physical and Chemical Properties Division in Boulder, Colorado was subcontracted under this project to study the issue in detail and to recommend a mercury vapor pressure equation that the vendors of mercury vapor pressure calibration units can use to calculate the elemental mercury vapor concentration in an equilibrium chamber at a particular temperature. As part of this study, a preliminary evaluation of calibration units from five vendors was made. The work was performed by NIST in Gaithersburg, MD and Joe Rovani from WRI who traveled to NIST as a Visiting Scientist.

  19. Field calibration of cup anemometers

    DEFF Research Database (Denmark)

    Schmidt Paulsen, Uwe; Mortensen, Niels Gylling; Hansen, Jens Carsten

    2007-01-01

    A field calibration method and results are described along with the experience gained with the method. The cup anemometers to be calibrated are mounted in a row on a 10-m high rig and calibrated in the free wind against a reference cup anemometer. The method has been reported [1] to improve...... the statistical bias on the data relative to calibrations carried out in a wind tunnel. The methodology is sufficiently accurate for calibration of cup anemometers used for wind resource assessments and provides a simple, reliable and cost-effective solution to cup anemometer calibration, especially suited...

  20. Mercury Calibration System

    Energy Technology Data Exchange (ETDEWEB)

    John Schabron; Eric Kalberer; Joseph Rovani; Mark Sanderson; Ryan Boysen; William Schuster

    2009-03-11

    U.S. Environmental Protection Agency (EPA) Performance Specification 12 in the Clean Air Mercury Rule (CAMR) states that a mercury CEM must be calibrated with National Institute for Standards and Technology (NIST)-traceable standards. In early 2009, a NIST traceable standard for elemental mercury CEM calibration still does not exist. Despite the vacature of CAMR by a Federal appeals court in early 2008, a NIST traceable standard is still needed for whatever regulation is implemented in the future. Thermo Fisher is a major vendor providing complete integrated mercury continuous emissions monitoring (CEM) systems to the industry. WRI is participating with EPA, EPRI, NIST, and Thermo Fisher towards the development of the criteria that will be used in the traceability protocols to be issued by EPA. An initial draft of an elemental mercury calibration traceability protocol was distributed for comment to the participating research groups and vendors on a limited basis in early May 2007. In August 2007, EPA issued an interim traceability protocol for elemental mercury calibrators. Various working drafts of the new interim traceability protocols were distributed in late 2008 and early 2009 to participants in the Mercury Standards Working Committee project. The protocols include sections on qualification and certification. The qualification section describes in general terms tests that must be conducted by the calibrator vendors to demonstrate that their calibration equipment meets the minimum requirements to be established by EPA for use in CAMR monitoring. Variables to be examined include linearity, ambient temperature, back pressure, ambient pressure, line voltage, and effects of shipping. None of the procedures were described in detail in the draft interim documents; however they describe what EPA would like to eventually develop. WRI is providing the data and results to EPA for use in developing revised experimental procedures and realistic acceptance criteria based on

  1. Third-party brachytherapy source calibrations and physicist responsibilities: report of the AAPM Low Energy Brachytherapy Source Calibration Working Group.

    Science.gov (United States)

    Butler, Wayne M; Bice, William S; DeWerd, Larry A; Hevezi, James M; Huq, M Saiful; Ibbott, Geoffrey S; Palta, Jatinder R; Rivard, Mark J; Seuntjens, Jan P; Thomadsen, Bruce R

    2008-09-01

    The AAPM Low Energy Brachytherapy Source Calibration Working Group was formed to investigate and recommend quality control and quality assurance procedures for brachytherapy sources prior to clinical use. Compiling and clarifying recommendations established by previous AAPM Task Groups 40, 56, and 64 were among the working group's charges, which also included the role of third-party handlers to perform loading and assay of sources. This document presents the findings of the working group on the responsibilities of the institutional medical physicist and a clarification of the existing AAPM recommendations in the assay of brachytherapy sources. Responsibility for the performance and attestation of source assays rests with the institutional medical physicist, who must use calibration equipment appropriate for each source type used at the institution. Such equipment and calibration procedures shall ensure secondary traceability to a national standard. For each multi-source implant, 10% of the sources or ten sources, whichever is greater, are to be assayed. Procedures for presterilized source packaging are outlined. The mean source strength of the assayed sources must agree with the manufacturer's stated strength to within 3%, or action must be taken to resolve the difference. Third party assays do not absolve the institutional physicist from the responsibility to perform the institutional measurement and attest to the strength of the implanted sources. The AAPM leaves it to the discretion of the institutional medical physicist whether the manufacturer's or institutional physicist's measured value should be used in performing dosimetry calculations.

  2. Lead Slowing-Down Spectrometry for Spent Fuel Assay: FY11 Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Glen A.; Casella, Andrew M.; Haight, R. C.; Anderson, Kevin K.; Danon, Yaron; Hatchett, D.; Becker, Bjorn; Devlin, M.; Imel, G. R.; Beller, D.; Gavron, A.; Kulisek, Jonathan A.; Bowyer, Sonya M.; Gesh, Christopher J.; O' Donnell, J. M.

    2011-08-01

    planned at LANL and RPI. LANL measurements will include a Pu sample, which is expected to provide more counts at longer slowing-down times to help identify discrepancies between experimental data and MCNPX simulations. RPI measurements will include the assay of an entire fresh fuel assembly for the study of self-shielding effects as well as the ability to detect diversion by detecting a missing fuel pin in the fuel assembly. The development of threshold neutron sensors will continue, and UNLV will calibrate existing ultra-depleted uranium deposits at ISU.

  3. Photometric calibrations for 21st century science

    Energy Technology Data Exchange (ETDEWEB)

    Kent, Stephen; /Fermilab; Kaiser, Mary Elizabeth; /Johns Hopkins U.; Deustua, Susana E.; /Baltimore, Space Telescope Sci.; Smith, J.Allyn; /Austin Peay State U.; Adelman, Saul; /Citadel Military Coll.; Allam, Sahar S.; /Fermilab; Baptista, Brian; /Indiana U.; Bohlin, Ralph C.; /Baltimore, Space Telescope Sci.; Clem, James L.; /Louisiana State U.; Conley, Alex; /Colorado U.; Edelstein, Jerry; /UC, Berkeley, Space Sci. Dept. /NOAO, Tucson

    2009-02-01

    The answers to fundamental science questions in astrophysics, ranging from the history of the expansion of the universe to the sizes of nearby stars, hinge on our ability to make precise measurements of diverse astronomical objects. As our knowledge of the underlying physics of objects improves along with advances in detectors and instrumentation, the limits on our capability to extract science from measurements is set, not by our lack of understanding of the nature of these objects, but rather by the most mundane of all issues: the precision with which we can calibrate observations in physical units. In principle, photometric calibration is a solved problem - laboratory reference standards such as blackbody furnaces achieve precisions well in excess of those needed for astrophysics. In practice, however, transferring the calibration from these laboratory standards to astronomical objects of interest is far from trivial - the transfer must reach outside the atmosphere, extend over 4{pi} steradians of sky, cover a wide range of wavelengths, and span an enormous dynamic range in intensity. Virtually all spectrophotometric observations today are calibrated against one or more stellar reference sources, such as Vega, which are themselves tied back to laboratory standards in a variety of ways. This system's accuracy is not uniform. Selected regions of the electromagnetic spectrum are calibrated extremely well, but discontinuities of a few percent still exist, e.g., between the optical and infrared. Independently, model stellar atmospheres are used to calibrate the spectra of selected white dwarf stars, e.g. the HST system, but the ultimate accuracy of this system should be verified against laboratory sources. Our traditional standard star systems, while sufficient until now, need to be improved and extended in order to serve future astrophysics experiments. This white paper calls for a program to improve upon and expand the current networks of

  4. The Calibration Reference Data System

    Science.gov (United States)

    Greenfield, P.; Miller, T.

    2016-07-01

    We describe a software architecture and implementation for using rules to determine which calibration files are appropriate for calibrating a given observation. This new system, the Calibration Reference Data System (CRDS), replaces what had been previously used for the Hubble Space Telescope (HST) calibration pipelines, the Calibration Database System (CDBS). CRDS will be used for the James Webb Space Telescope (JWST) calibration pipelines, and is currently being used for HST calibration pipelines. CRDS can be easily generalized for use in similar applications that need a rules-based system for selecting the appropriate item for a given dataset; we give some examples of such generalizations that will likely be used for JWST. The core functionality of the Calibration Reference Data System is available under an Open Source license. CRDS is briefly contrasted with a sampling of other similar systems used at other observatories.

  5. Lidar calibration experiments

    DEFF Research Database (Denmark)

    Ejsing Jørgensen, Hans; Mikkelsen, T.; Streicher, J.

    1997-01-01

    A series of atmospheric aerosol diffusion experiments combined with lidar detection was conducted to evaluate and calibrate an existing retrieval algorithm for aerosol backscatter lidar systems. The calibration experiments made use of two (almost) identical mini-lidar systems for aerosol cloud...... detection to test the reproducibility and uncertainty of lidars. Lidar data were obtained from both single-ended and double-ended Lidar configurations. A backstop was introduced in one of the experiments and a new method was developed where information obtained from the backstop can be used in the inversion...... algorithm. Independent in-situ aerosol plume concentrations were obtained from a simultaneous tracer gas experiment with SF6, and comparisons with the two lidars were made. The study shows that the reproducibility of the lidars is within 15%, including measurements from both sides of a plume...

  6. Optical tweezers absolute calibration

    CERN Document Server

    Dutra, R S; Neto, P A Maia; Nussenzveig, H M

    2014-01-01

    Optical tweezers are highly versatile laser traps for neutral microparticles, with fundamental applications in physics and in single molecule cell biology. Force measurements are performed by converting the stiffness response to displacement of trapped transparent microspheres, employed as force transducers. Usually, calibration is indirect, by comparison with fluid drag forces. This can lead to discrepancies by sizable factors. Progress achieved in a program aiming at absolute calibration, conducted over the past fifteen years, is briefly reviewed. Here we overcome its last major obstacle, a theoretical overestimation of the peak stiffness, within the most employed range for applications, and we perform experimental validation. The discrepancy is traced to the effect of primary aberrations of the optical system, which are now included in the theory. All required experimental parameters are readily accessible. Astigmatism, the dominant effect, is measured by analyzing reflected images of the focused laser spo...

  7. Astrid-2 SSC ASUMagnetic Calibration

    DEFF Research Database (Denmark)

    Primdahl, Fritz

    1997-01-01

    Report of the inter calibration between the starcamera and the fluxgate magnetometer onboard the ASTRID-2 satellite. This calibration was performed in the night between the 15. and 16. May 1997 at the Lovö magnetic observatory.......Report of the inter calibration between the starcamera and the fluxgate magnetometer onboard the ASTRID-2 satellite. This calibration was performed in the night between the 15. and 16. May 1997 at the Lovö magnetic observatory....

  8. Calibration Facilities for NIF

    Energy Technology Data Exchange (ETDEWEB)

    Perry, T.S.

    2000-06-15

    The calibration facilities will be dynamic and will change to meet the needs of experiments. Small sources, such as the Manson Source should be available to everyone at any time. Carrying out experiments at Omega is providing ample opportunity for practice in pre-shot preparation. Hopefully, the needs that are demonstrated in these experiments will assure the development of (or keep in service) facilities at each of the laboratories that will be essential for in-house preparation for experiments at NIF.

  9. Mesoscale hybrid calibration artifact

    Science.gov (United States)

    Tran, Hy D.; Claudet, Andre A.; Oliver, Andrew D.

    2010-09-07

    A mesoscale calibration artifact, also called a hybrid artifact, suitable for hybrid dimensional measurement and the method for make the artifact. The hybrid artifact has structural characteristics that make it suitable for dimensional measurement in both vision-based systems and touch-probe-based systems. The hybrid artifact employs the intersection of bulk-micromachined planes to fabricate edges that are sharp to the nanometer level and intersecting planes with crystal-lattice-defined angles.

  10. Calibration of Underwater Sound Transducers

    Directory of Open Access Journals (Sweden)

    H.R.S. Sastry

    1983-07-01

    Full Text Available The techniques of calibration of underwater sound transducers for farfield, near-field and closed environment conditions are reviewed in this paper .The design of acoustic calibration tank is mentioned. The facilities available at Naval Physical & Oceanographic Laboratory, Cochin for calibration of transducers are also listed.

  11. Internet-based calibration of a multifunction calibrator

    Energy Technology Data Exchange (ETDEWEB)

    BUNTING BACA,LISA A.; DUDA JR.,LEONARD E.; WALKER,RUSSELL M.; OLDHAM,NILE; PARKER,MARK

    2000-04-17

    A new way of providing calibration services is evolving which employs the Internet to expand present capabilities and make the calibration process more interactive. Sandia National Laboratories and the National Institute of Standards and Technology are collaborating to set up and demonstrate a remote calibration of multifunction calibrators using this Internet-based technique that is becoming known as e-calibration. This paper describes the measurement philosophy and the Internet resources that can provide real-time audio/video/data exchange, consultation and training, as well as web-accessible test procedures, software and calibration reports. The communication system utilizes commercial hardware and software that should be easy to integrate into most calibration laboratories.

  12. Improved PCR assay for the species-specific identification and quantitation of Legionella pneumophila in water.

    Science.gov (United States)

    Cho, Min Seok; Ahn, Tae-Young; Joh, Kiseong; Lee, Eui Seok; Park, Dong Suk

    2015-11-01

    Legionellosis outbreak is a major global health care problem. However, current Legionella risk assessments may be compromised by uncertainties in Legionella detection methods, infectious dose, and strain infectivity. These limitations may place public health at significant risk, leading to significant monetary losses in health care. However, there are still unmet needs for its rapid identification and monitoring of legionellae in water systems. Therefore, in the present study, a primer set was designed based on a LysR-type transcriptional regulator (LTTR) family protein gene of Legionella pneumophila subsp. pneumophila str. Philadelphia 1 because it was found that this gene is structurally diverse among species through BLAST searches. The specificity of the primer set was evaluated using genomic DNA from 6 strains of L. pneumophila, 5 type strains of other related Legionella species, and other 29 reference pathogenic bacteria. The primer set used in the PCR assay amplified a 264-bp product for only targeted six strains of L. pneumophila. The assay was also able to detect at least 1.39 × 10(3) copies/μl of cloned amplified target DNA using purified DNA or 7.4 × 10(0) colony-forming unit per reaction when using calibrated cell suspension. In addition, the sensitivity and specificity of this assay were confirmed by successful detection of Legionella pneumophila in environmental water samples.

  13. Design and calibration of the AWCC for measuring uranium hexafluoride

    Energy Technology Data Exchange (ETDEWEB)

    Wenz, T.R.; Menlove, H.O.; WSalton, G.; Baca, J.

    1995-08-01

    An Active Well Coincidence Counter (AWCC) has been modified to measure variable enrichment uranium hexafluoride (UF{sub 6}) in storage bottles. An active assay technique was used to measure the {sup 235}U content because of the small quantity (nominal loading of 2 kg UF{sub 6}) and nonuniform distribution of UF{sub 6} in the storage bottles. A new insert was designed for the AWCC composed of graphite containing four americium-lithium sources. Monte Carlo calculations were used to design the insert and to calibrate the detector. Benchmark measurements and calculations were performed using uranium oxide resulted in assay values that agreed within 2 to 3% of destructive assay values. In addition to UF{sub 6}, the detector was also calibrated for HEU ingots, billets, and alloy scrap using the standard Mode 1 end-plug configuration.

  14. Identity, Diversity and Diversity Management

    DEFF Research Database (Denmark)

    Holck, Lotte; Muhr, Sara Louise; Villeseche, Florence

    2016-01-01

    The purpose of this paper is to examine the relationship between the identity and diversity literatures and discuss how a better understanding of the theoretical connections between the two informs both diversity research and diversity management practices. Design/methodology/approach – Literature...... review followed by a discussion of the theoretical and practical consequences of connecting the identity and diversity literatures. Findings – The authors inform future research in three ways. First, by showing how definitions of identity influence diversity theorizing in specific ways. Second......, the authors explore how such definitions entail distinct foci regarding how diversity should be analyzed and interventions actioned. Third, the authors discuss how theoretical coherence between definitions of identity and diversity perspectives – as well as knowledge about a perspective’s advantages...

  15. Mercury CEM Calibration

    Energy Technology Data Exchange (ETDEWEB)

    John Schabron; Joseph Rovani; Mark Sanderson

    2008-02-29

    Mercury continuous emissions monitoring systems (CEMS) are being implemented in over 800 coal-fired power plant stacks. The power industry desires to conduct at least a full year of monitoring before the formal monitoring and reporting requirement begins on January 1, 2009. It is important for the industry to have available reliable, turnkey equipment from CEM vendors. Western Research Institute (WRI) is working closely with the Electric Power Research Institute (EPRI), the National Institute of Standards and Technology (NIST), and the Environmental Protection Agency (EPA) to facilitate the development of the experimental criteria for a NIST traceability protocol for dynamic elemental mercury vapor generators. The generators are used to calibrate mercury CEMs at power plant sites. The Clean Air Mercury Rule (CAMR) which was published in the Federal Register on May 18, 2005 requires that calibration be performed with NIST-traceable standards (Federal Register 2007). Traceability procedures will be defined by EPA. An initial draft traceability protocol was issued by EPA in May 2007 for comment. In August 2007, EPA issued an interim traceability protocol for elemental mercury generators (EPA 2007). The protocol is based on the actual analysis of the output of each calibration unit at several concentration levels ranging initially from about 2-40 {micro}g/m{sup 3} elemental mercury, and in the future down to 0.2 {micro}g/m{sup 3}, and this analysis will be directly traceable to analyses by NIST. The document is divided into two separate sections. The first deals with the qualification of generators by the vendors for use in mercury CEM calibration. The second describes the procedure that the vendors must use to certify the generator models that meet the qualification specifications. The NIST traceable certification is performance based, traceable to analysis using isotope dilution inductively coupled plasma/mass spectrometry performed by NIST in Gaithersburg, MD. The

  16. CALIBRATED HYDRODYNAMIC MODEL

    Directory of Open Access Journals (Sweden)

    Sezar Gülbaz

    2015-01-01

    Full Text Available The land development and increase in urbanization in a watershed affect water quantityand water quality. On one hand, urbanization provokes the adjustment of geomorphicstructure of the streams, ultimately raises peak flow rate which causes flood; on theother hand, it diminishes water quality which results in an increase in Total SuspendedSolid (TSS. Consequently, sediment accumulation in downstream of urban areas isobserved which is not preferred for longer life of dams. In order to overcome thesediment accumulation problem in dams, the amount of TSS in streams and inwatersheds should be taken under control. Low Impact Development (LID is a BestManagement Practice (BMP which may be used for this purpose. It is a land planningand engineering design method which is applied in managing storm water runoff inorder to reduce flooding as well as simultaneously improve water quality. LID includestechniques to predict suspended solid loads in surface runoff generated over imperviousurban surfaces. In this study, the impact of LID-BMPs on surface runoff and TSS isinvestigated by employing a calibrated hydrodynamic model for Sazlidere Watershedwhich is located in Istanbul, Turkey. For this purpose, a calibrated hydrodynamicmodel was developed by using Environmental Protection Agency Storm WaterManagement Model (EPA SWMM. For model calibration and validation, we set up arain gauge and a flow meter into the field and obtain rainfall and flow rate data. Andthen, we select several LID types such as retention basins, vegetative swales andpermeable pavement and we obtain their influence on peak flow rate and pollutantbuildup and washoff for TSS. Consequently, we observe the possible effects ofLID on surface runoff and TSS in Sazlidere Watershed.

  17. ALTEA: The instrument calibration

    Energy Technology Data Exchange (ETDEWEB)

    Zaconte, V. [INFN and University of Rome Tor Vergata, Department of Physics, Via della Ricerca Scientifica 1, 00133 Rome (Italy)], E-mail: livio.narici@roma2.infn.it; Belli, F.; Bidoli, V.; Casolino, M.; Di Fino, L.; Narici, L.; Picozza, P.; Rinaldi, A. [INFN and University of Rome Tor Vergata, Department of Physics, Via della Ricerca Scientifica 1, 00133 Rome (Italy); Sannita, W.G. [DISM, University of Genova, Genova (Italy); Department of Psychiatry, SUNY, Stoony Brook, NY (United States); Finetti, N.; Nurzia, G.; Rantucci, E.; Scrimaglio, R.; Segreto, E. [Department of Physics, University and INFN, L' Aquila (Italy); Schardt, D. [GSI/Biophysik, Darmstadt (Germany)

    2008-05-15

    The ALTEA program is an international and multi-disciplinary project aimed at studying particle radiation in space environment and its effects on astronauts' brain functions, as the anomalous perception of light flashes first reported during Apollo missions. The ALTEA space facility includes a 6-silicon telescopes particle detector, and is onboard the International Space Station (ISS) since July 2006. In this paper, the detector calibration at the heavy-ion synchrotron SIS18 at GSI Darmstadt will be presented and compared to the Geant 3 Monte Carlo simulation. Finally, the results of a neural network analysis that was used for ion discrimination on fragmentation data will also be presented.

  18. Dynamic Torque Calibration Unit

    Science.gov (United States)

    Agronin, Michael L.; Marchetto, Carl A.

    1989-01-01

    Proposed dynamic torque calibration unit (DTCU) measures torque in rotary actuator components such as motors, bearings, gear trains, and flex couplings. Unique because designed specifically for testing components under low rates. Measures torque in device under test during controlled steady rotation or oscillation. Rotor oriented vertically, supported by upper angular-contact bearing and lower radial-contact bearing that floats axially to prevent thermal expansion from loading bearings. High-load capacity air bearing available to replace ball bearings when higher load capacity or reduction in rate noise required.

  19. Microbead agglutination based assays

    KAUST Repository

    Kodzius, Rimantas

    2013-01-21

    We report a simple and rapid room temperature assay for point-of-care (POC) testing that is based on specific agglutination. Agglutination tests are based on aggregation of microbeads in the presence of a specific analyte thus enabling the macroscopic observation. Such tests are most often used to explore antibody-antigen reactions. Agglutination has been used for protein assays using a biotin/streptavidin system as well as a hybridization based assay. The agglutination systems are prone to selftermination of the linking analyte, prone to active site saturation and loss of agglomeration at high analyte concentrations. We investigated the molecular target/ligand interaction, explaining the common agglutination problems related to analyte self-termination, linkage of the analyte to the same bead instead of different microbeads. We classified the agglutination process into three kinds of assays: a two- component assay, a three-component assay and a stepped three- component assay. Although we compared these three kinds of assays for recognizing DNA and protein molecules, the assay can be used for virtually any molecule, including ions and metabolites. In total, the optimized assay permits detecting analytes with high sensitivity in a short time, 5 min, at room temperature. Such a system is appropriate for POC testing.

  20. A Simple Accelerometer Calibrator

    Science.gov (United States)

    Salam, R. A.; Islamy, M. R. F.; Munir, M. M.; Latief, H.; Irsyam, M.; Khairurrijal

    2016-08-01

    High possibility of earthquake could lead to the high number of victims caused by it. It also can cause other hazards such as tsunami, landslide, etc. In that case it requires a system that can examine the earthquake occurrence. Some possible system to detect earthquake is by creating a vibration sensor system using accelerometer. However, the output of the system is usually put in the form of acceleration data. Therefore, a calibrator system for accelerometer to sense the vibration is needed. In this study, a simple accelerometer calibrator has been developed using 12 V DC motor, optocoupler, Liquid Crystal Display (LCD) and AVR 328 microcontroller as controller system. The system uses the Pulse Wave Modulation (PWM) form microcontroller to control the motor rotational speed as response to vibration frequency. The frequency of vibration was read by optocoupler and then those data was used as feedback to the system. The results show that the systems could control the rotational speed and the vibration frequencies in accordance with the defined PWM.

  1. Diversity Management

    DEFF Research Database (Denmark)

    Ravazzani, Silvia

    2016-01-01

    This entry provides an overview of diversity management which, in the context of organizations, consists in the strategic process of harnessing the potential of all employees to create an inclusive environment and, at the same time, contribute to meeting organizational goals. The entry first...... describes the complex construct of diversity that has been variously conceptualized in the literature, embracing multiple social and informational diversity dimensions such as gender, age, culture, values, and workstyle. This is followed by illustration of the historical development of diversity-management...... discourse and practice, and possible overarching approaches guiding organizations. It goes on to elucidate elements linked to the implementation of diversity management: positive and negative outcomes, most spread practices including communication, and contingency factors shaping the understanding...

  2. Absolute nuclear material assay

    Science.gov (United States)

    Prasad, Manoj K [Pleasanton, CA; Snyderman, Neal J [Berkeley, CA; Rowland, Mark S [Alamo, CA

    2012-05-15

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  3. Internal Water Vapor Photoacoustic Calibration

    Science.gov (United States)

    Pilgrim, Jeffrey S.

    2009-01-01

    Water vapor absorption is ubiquitous in the infrared wavelength range where photoacoustic trace gas detectors operate. This technique allows for discontinuous wavelength tuning by temperature-jumping a laser diode from one range to another within a time span suitable for photoacoustic calibration. The use of an internal calibration eliminates the need for external calibrated reference gases. Commercial applications include an improvement of photoacoustic spectrometers in all fields of use.

  4. Everyday Diversity

    Directory of Open Access Journals (Sweden)

    Christina Ho

    2015-03-01

    Full Text Available The Cosmopolitan Civil Societies Journal has been an important forum for discussing issues around cultural diversity. Articles on cultural diversity have been present in virtually every issue of the journal. These have ranged from conceptual pieces on cosmopolitanism, identity, dialogue, prejudice, pluralism, cultural and social capital and social inclusion, to articles embedded in empirical research on ethnic precincts and segregation in cities, experiences of religious minorities, immigrant entrepreneurs, and more. Over its five year history, the journal has also had themed editions on cultural diversity issues, including one on embracing diversity in sport, and another on the Chinese in Australian politics. The scope of this work has been wide, and authors have brought a range of disciplinary and methodological approaches to the journal.   The purpose of this paper is to draw together some of the work that has been published around cultural diversity, particularly relating to everyday experiences of cosmopolitanism and racism. Focusing on everyday social relations has been an important part of recent scholarship on cultural diversity in Australia (e.g. Wise and Velayutham 2009. In contrast to research framed around multicultural policy or mediated representations of diversity, the scholarship of the ‘everyday’ aims to explore people’s lived experiences and daily interactions with others.

  5. Field calibration of cup anemometers

    DEFF Research Database (Denmark)

    Kristensen, L.; Jensen, G.; Hansen, A.

    2001-01-01

    An outdoor calibration facility for cup anemometers, where the signals from 10 anemometers of which at least one is a reference can be can be recorded simultaneously, has been established. The results are discussed with special emphasis on the statisticalsignificance of the calibration expressions....... It is concluded that the method has the advantage that many anemometers can be calibrated accurately with a minimum of work and cost. The obvious disadvantage is that the calibration of a set of anemometersmay take more than one month in order to have wind speeds covering a sufficiently large magnitude range...

  6. Radiological Calibration and Standards Facility

    Data.gov (United States)

    Federal Laboratory Consortium — PNNL maintains a state-of-the-art Radiological Calibration and Standards Laboratory on the Hanford Site at Richland, Washington. Laboratory staff provide expertise...

  7. SURF Model Calibration Strategy

    Energy Technology Data Exchange (ETDEWEB)

    Menikoff, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-10

    SURF and SURFplus are high explosive reactive burn models for shock initiation and propagation of detonation waves. They are engineering models motivated by the ignition & growth concept of high spots and for SURFplus a second slow reaction for the energy release from carbon clustering. A key feature of the SURF model is that there is a partial decoupling between model parameters and detonation properties. This enables reduced sets of independent parameters to be calibrated sequentially for the initiation and propagation regimes. Here we focus on a methodology for tting the initiation parameters to Pop plot data based on 1-D simulations to compute a numerical Pop plot. In addition, the strategy for tting the remaining parameters for the propagation regime and failure diameter is discussed.

  8. RX130 Robot Calibration

    Science.gov (United States)

    Fugal, Mario

    2012-10-01

    In order to create precision magnets for an experiment at Oak Ridge National Laboratory, a new reverse engineering method has been proposed that uses the magnetic scalar potential to solve for the currents necessary to produce the desired field. To make the magnet it is proposed to use a copper coated G10 form, upon which a drill, mounted on a robotic arm, will carve wires. The accuracy required in the manufacturing of the wires exceeds nominal robot capabilities. However, due to the rigidity as well as the precision servo motor and harmonic gear drivers, there are robots capable of meeting this requirement with proper calibration. Improving the accuracy of an RX130 to be within 35 microns (the accuracy necessary of the wires) is the goal of this project. Using feedback from a displacement sensor, or camera and inverse kinematics it is possible to achieve this accuracy.

  9. Calibration of Nanopositioning Stages

    Directory of Open Access Journals (Sweden)

    Ning Tan

    2015-12-01

    Full Text Available Accuracy is one of the most important criteria for the performance evaluation of micro- and nanorobots or systems. Nanopositioning stages are used to achieve the high positioning resolution and accuracy for a wide and growing scope of applications. However, their positioning accuracy and repeatability are not well known and difficult to guarantee, which induces many drawbacks for many applications. For example, in the mechanical characterisation of biological samples, it is difficult to perform several cycles in a repeatable way so as not to induce negative influences on the study. It also prevents one from controlling accurately a tool with respect to a sample without adding additional sensors for closed loop control. This paper aims at quantifying the positioning repeatability and accuracy based on the ISO 9283:1998 standard, and analyzing factors influencing positioning accuracy onto a case study of 1-DoF (Degree-of-Freedom nanopositioning stage. The influence of thermal drift is notably quantified. Performances improvement of the nanopositioning stage are then investigated through robot calibration (i.e., open-loop approach. Two models (static and adaptive models are proposed to compensate for both geometric errors and thermal drift. Validation experiments are conducted over a long period (several days showing that the accuracy of the stage is improved from typical micrometer range to 400 nm using the static model and even down to 100 nm using the adaptive model. In addition, we extend the 1-DoF calibration to multi-DoF with a case study of a 2-DoF nanopositioning robot. Results demonstrate that the model efficiently improved the 2D accuracy from 1400 nm to 200 nm.

  10. Research highlights: digital assays on chip.

    Science.gov (United States)

    Kim, Donghyuk; Wei, Qingshan; Kong, Janay Elise; Ozcan, Aydogan; Di Carlo, Dino

    2015-01-07

    The ability to break up a volume of fluid into smaller pieces that are confined or separated to prevent molecular communication/transport is a key capability intrinsic to microfluidic systems. This capability has been used to develop or implement digital versions of traditional molecular analysis assays, including digital PCR and digital immunoassays/ELISA. In these digital versions, the concentration of the target analyte is in a range such that, when sampled into smaller fluid volumes, either a single molecule or no molecule may be present. Subsequent amplification is sensitive enough to obtain a digital readout of the presence of these target molecules. Advantages of such approaches that are claimed include quantification without calibration and robustness to variations in reaction conditions or times because the digital readout is less sensitive to absolute signal intensity levels. Weaknesses of digital approaches include a lower dynamic range of concentrations over which the assay is sensitive, which depends on the total volume that can be analyzed. We highlight recent efforts to expand the dynamic range of digital assays based on exploiting reaction/diffusion phenomena. A side-by-side study that evaluates the strengths of digital assays reveals that the majority of these claims are supported, with specific caveats. Finally, we highlight approaches to apply digital assays to analyze new types of reactions, including the active transport of protons across membranes by ATPases at the single protein level - perhaps opening up new biophysical understanding and screening opportunities, similar to widely deployed single-molecule ion channel analysis.

  11. Understanding Diversity

    NARCIS (Netherlands)

    D.L. van Knippenberg (Daan)

    2007-01-01

    textabstractDaan van Knippenberg is Professor of Organizational Behavior at RSM Erasmus University, Erasmus University Rotterdam, The Netherlands. His research interests include work group performance, especially work group diversity and group decision making, leadership, in particular the roles of

  12. Gender Diversities

    DEFF Research Database (Denmark)

    Agustin, Lise Rolandsen; Siim, Birte

    2014-01-01

    The article analyses the European Year for Combating Poverty and Social Exclusion (2010) (EY 2010) with the aim of identifying the nature of gender diversities in EU policies. We argue that the EU handles issues related to gender and diversity in particular ways; this approach is characterized...... by non-citizen/citizen and redistribution/recognition divisions. Employing intersectionality as the methodological approach to gender diversities, the article shows how gender and ethnicity are articulated in the policy-making process which led to the adoption of EY 201, the activities undertaken during...... the EY 2010, and the evaluation of EY 2010. The case study is suitable for developing a dynamic multi-level model for analysing gendered diversities at the transnationmal level: It illustrates how the EU policy frame interacts with particular national contexts in promoting or hundering the advancement...

  13. Challenges in X-band Weather Radar Data Calibration

    DEFF Research Database (Denmark)

    Thorndahl, Søren; Rasmussen, Michael R.

    2009-01-01

    Application of weather radar data in urban hydrology is evolving and radar data is now applied for both modelling, analysis and real time control purposes. In these contexts, it is all-important that the radar data well calibrated and adjusted in order to obtain valid quantitative precipitation...... estimates. This paper compares two calibration procedures for a small marine X-band radar by comparing radar data with rain gauge data. Validation shows a very good consensus with regards to precipitation volumes, but more diverse results on peak rain intensities....

  14. Tectonic calibrations in molecular dating

    Institute of Scientific and Technical Information of China (English)

    Ullasa KODANDARAMAIAH

    2011-01-01

    Molecular dating techniques require the use of calibrations, which are usually fossil or geological vicariance-based.Fossil calibrations have been criticised because they result only in minimum age estimates. Based on a historical biogeographic perspective, Ⅰ suggest that vicariance-based calibrations are more dangerous. Almost all analytical methods in historical biogeography are strongly biased towards inferring vicariance, hence vicariance identified through such methods is unreliable. Other studies, especially of groups found on Gondwanan fragments, have simply assumed vicariance. Although it was previously believed that vicariance was the predominant mode of speciation, mounting evidence now indicates that speciation by dispersal is common, dominating vicariance in several groups. Moreover, the possibility of speciation having occurred before the said geological event cannot be precluded. Thus, geological calibrations can under- or overestimate times, whereas fossil calibrations always result in minimum estimates. Another major drawback of vicariant calibrations is the problem of circular reasoning when the resulting estimates are used to infer ages of biogeographic events. Ⅰ argue that fossil-based dating is a superior alternative to vicariance, primarily because the strongest assumption in the latter, that speciation was caused by the said geological process, is more often than not the most tenuous. When authors prefer to use a combination of fossil and vicariant calibrations, one suggestion is to report results both with and without inclusion of the geological constraints. Relying solely on vicariant calibrations should be strictly avoided.

  15. Cobalt source calibration

    Energy Technology Data Exchange (ETDEWEB)

    Rizvi, H.M.

    1999-12-03

    The data obtained from these tests determine the dose rate of the two cobalt sources in SRTC. Building 774-A houses one of these sources while the other resides in room C-067 of Building 773-A. The data from this experiment shows the following: (1) The dose rate of the No.2 cobalt source in Building 774-A measured 1.073 x 10{sup 5} rad/h (June 17, 1999). The dose rate of the Shepherd Model 109 Gamma cobalt source in Building 773-A measured 9.27 x 10{sup 5} rad/h (June 25, 1999). These rates come from placing the graduated cylinder containing the dosimeter solution in the center of the irradiation chamber. (2) Two calibration tests in the 774-A source placed the graduated cylinder with the dosimeter solution approximately 1.5 inches off center in the axial direction. This movement of the sample reduced the measured dose rate 0.92% from 1.083 x 10{sup 5} rad/h to 1.073 x 10{sup 5} rad/h. and (3) A similar test in the cobalt source in 773-A placed the graduated cylinder approximately 2.0 inches off center in the axial direction. This change in position reduced the measured dose rate by 10.34% from 1.036 x 10{sup 6} to 9.27 x 10{sup 5}. This testing used chemical dosimetry to measure the dose rate of a radioactive source. In this method, one determines the dose by the chemical change that takes place in the dosimeter. For this calibration experiment, the author used a Fricke (ferrous ammonium sulfate) dosimeter. This solution works well for dose rates to 10{sup 7} rad/h. During irradiation of the Fricke dosimeter solution the Fe{sup 2+} ions ionize to Fe{sup 3+}. When this occurs, the solution acquires a slightly darker tint (not visible to the human eye). To determine the magnitude of the change in Fe ions, one places the solution in an UV-VIS Spectrophotometer. The UV-VIS Spectrophotometer measures the absorbency of the solution. Dividing the absorbency by the total time (in minutes) of exposure yields the dose rate.

  16. The Advanced LIGO Photon Calibrators

    CERN Document Server

    Karki, S; Kandhasamy, S; Abbott, B P; Abbott, T D; Anders, E H; Berliner, J; Betzwieser, J; Daveloza, H P; Cahillane, C; Canete, L; Conley, C; Gleason, J R; Goetz, E; Kissel, J S; Izumi, K; Mendell, G; Quetschke, V; Rodruck, M; Sachdev, S; Sadecki, T; Schwinberg, P B; Sottile, A; Wade, M; Weinstein, A J; West, M; Savage, R L

    2016-01-01

    The two interferometers of the Laser Interferometry Gravitaional-wave Observatory (LIGO) recently detected gravitational waves from the mergers of binary black hole systems. Accurate calibration of the output of these detectors was crucial for the observation of these events, and the extraction of parameters of the sources. The principal tools used to calibrate the responses of the second-generation (Advanced) LIGO detectors to gravitational waves are systems based on radiation pressure and referred to as Photon Calibrators. These systems, which were completely redesigned for Advanced LIGO, include several significant upgrades that enable them to meet the calibration requirements of second-generation gravitational wave detectors in the new era of gravitational-wave astronomy. We report on the design, implementation, and operation of these Advanced LIGO Photon Calibrators that are currently providing fiducial displacements on the order of $10^{-18}$ m/$\\sqrt{\\textrm{Hz}}$ with accuracy and precision of better ...

  17. The Advanced LIGO photon calibrators

    Science.gov (United States)

    Karki, S.; Tuyenbayev, D.; Kandhasamy, S.; Abbott, B. P.; Abbott, T. D.; Anders, E. H.; Berliner, J.; Betzwieser, J.; Cahillane, C.; Canete, L.; Conley, C.; Daveloza, H. P.; De Lillo, N.; Gleason, J. R.; Goetz, E.; Izumi, K.; Kissel, J. S.; Mendell, G.; Quetschke, V.; Rodruck, M.; Sachdev, S.; Sadecki, T.; Schwinberg, P. B.; Sottile, A.; Wade, M.; Weinstein, A. J.; West, M.; Savage, R. L.

    2016-11-01

    The two interferometers of the Laser Interferometry Gravitational-wave Observatory (LIGO) recently detected gravitational waves from the mergers of binary black hole systems. Accurate calibration of the output of these detectors was crucial for the observation of these events and the extraction of parameters of the sources. The principal tools used to calibrate the responses of the second-generation (Advanced) LIGO detectors to gravitational waves are systems based on radiation pressure and referred to as photon calibrators. These systems, which were completely redesigned for Advanced LIGO, include several significant upgrades that enable them to meet the calibration requirements of second-generation gravitational wave detectors in the new era of gravitational-wave astronomy. We report on the design, implementation, and operation of these Advanced LIGO photon calibrators that are currently providing fiducial displacements on the order of 1 0-18m /√{Hz } with accuracy and precision of better than 1%.

  18. TIME CALIBRATED OSCILLOSCOPE SWEEP CIRCUIT

    Science.gov (United States)

    Smith, V.L.; Carstensen, H.K.

    1959-11-24

    An improved time calibrated sweep circuit is presented, which extends the range of usefulness of conventional oscilloscopes as utilized for time calibrated display applications in accordance with U. S. Patent No. 2,832,002. Principal novelty resides in the provision of a pair of separate signal paths, each of which is phase and amplitude adjustable, to connect a high-frequency calibration oscillator to the output of a sawtooth generator also connected to the respective horizontal deflection plates of an oscilloscope cathode ray tube. The amplitude and phase of the calibration oscillator signals in the two signal paths are adjusted to balance out feedthrough currents capacitively coupled at high frequencies of the calibration oscillator from each horizontal deflection plate to the vertical plates of the cathode ray tube.

  19. Automated calibration of multistatic arrays

    Energy Technology Data Exchange (ETDEWEB)

    Henderer, Bruce

    2017-03-14

    A method is disclosed for calibrating a multistatic array having a plurality of transmitter and receiver pairs spaced from one another along a predetermined path and relative to a plurality of bin locations, and further being spaced at a fixed distance from a stationary calibration implement. A clock reference pulse may be generated, and each of the transmitters and receivers of each said transmitter/receiver pair turned on at a monotonically increasing time delay interval relative to the clock reference pulse. Ones of the transmitters and receivers may be used such that a previously calibrated transmitter or receiver of a given one of the transmitter/receiver pairs is paired with a subsequently un-calibrated one of the transmitters or receivers of an immediately subsequently positioned transmitter/receiver pair, to calibrate the transmitter or receiver of the immediately subsequent transmitter/receiver pair.

  20. Antenna Calibration and Measurement Equipment

    Science.gov (United States)

    Rochblatt, David J.; Cortes, Manuel Vazquez

    2012-01-01

    A document describes the Antenna Calibration & Measurement Equipment (ACME) system that will provide the Deep Space Network (DSN) with instrumentation enabling a trained RF engineer at each complex to perform antenna calibration measurements and to generate antenna calibration data. This data includes continuous-scan auto-bore-based data acquisition with all-sky data gathering in support of 4th order pointing model generation requirements. Other data includes antenna subreflector focus, system noise temperature and tipping curves, antenna efficiency, reports system linearity, and instrument calibration. The ACME system design is based on the on-the-fly (OTF) mapping technique and architecture. ACME has contributed to the improved RF performance of the DSN by approximately a factor of two. It improved the pointing performances of the DSN antennas and productivity of its personnel and calibration engineers.

  1. Comparison of a Multiplex Flow Cytometric Assay with Enzyme-Linked Immunosorbent Assay for Quantitation of Antibodies to Tetanus, Diphtheria, and Haemophilus influenzae Type b

    OpenAIRE

    Pickering, Jerry W.; Martins, Thomas B.; Schroder, M. Carl; Hill, Harry R.

    2002-01-01

    We developed a multiplexed indirect immunofluorescence assay for antibodies to Haemophilus influenza type b (Hib) polysaccharide and the toxoids of Clostridium tetani (Tet) and Corynebacterium diphtheriae (Dip) based on the Luminex multiple-analyte profiling system. A pooled serum standard was calibrated against World Health Organization standards for Dip and Tet and an international standard for Hib. The multiplexed Luminex assay was compared to individual enzyme-linked immunosorbent assays ...

  2. A calibrated Franklin chimes

    Science.gov (United States)

    Gonta, Igor; Williams, Earle

    1994-05-01

    Benjamin Franklin devised a simple yet intriguing device to measure electrification in the atmosphere during conditions of foul weather. He constructed a system of bells, one of which was attached to a conductor that was suspended vertically above his house. The device is illustrated in a well-known painting of Franklin (Cohen, 1985). The elevated conductor acquired a potential due to the electric field in the atmosphere and caused a brass ball to oscillate between two bells. The purpose of this study is to extend Franklin's idea by constructing a set of 'chimes' which will operate both in fair and in foul weather conditions. In addition, a mathematical relationship will be established between the frequency of oscillation of a metallic sphere in a simplified geometry and the potential on one plate due to the electrification of the atmosphere. Thus it will be possible to calibrate the 'Franklin Chimes' and to obtain a nearly instantaneous measurement of the potential of the elevated conductor in both fair and foul weather conditions.

  3. Mercury Continuous Emmission Monitor Calibration

    Energy Technology Data Exchange (ETDEWEB)

    John Schabron; Eric Kalberer; Ryan Boysen; William Schuster; Joseph Rovani

    2009-03-12

    Mercury continuous emissions monitoring systems (CEMs) are being implemented in over 800 coal-fired power plant stacks throughput the U.S. Western Research Institute (WRI) is working closely with the Electric Power Research Institute (EPRI), the National Institute of Standards and Technology (NIST), and the Environmental Protection Agency (EPA) to facilitate the development of the experimental criteria for a NIST traceability protocol for dynamic elemental mercury vapor calibrators/generators. These devices are used to calibrate mercury CEMs at power plant sites. The Clean Air Mercury Rule (CAMR) which was published in the Federal Register on May 18, 2005 and vacated by a Federal appeals court in early 2008 required that calibration be performed with NIST-traceable standards. Despite the vacature, mercury emissions regulations in the future will require NIST traceable calibration standards, and EPA does not want to interrupt the effort towards developing NIST traceability protocols. The traceability procedures will be defined by EPA. An initial draft traceability protocol was issued by EPA in May 2007 for comment. In August 2007, EPA issued a conceptual interim traceability protocol for elemental mercury calibrators. The protocol is based on the actual analysis of the output of each calibration unit at several concentration levels ranging initially from about 2-40 {micro}g/m{sup 3} elemental mercury, and in the future down to 0.2 {micro}g/m{sup 3}, and this analysis will be directly traceable to analyses by NIST. The EPA traceability protocol document is divided into two separate sections. The first deals with the qualification of calibrator models by the vendors for use in mercury CEM calibration. The second describes the procedure that the vendors must use to certify the calibrators that meet the qualification specifications. The NIST traceable certification is performance based, traceable to analysis using isotope dilution inductively coupled plasma

  4. Design, construction, and validation of a modular library of sequence diversity standards for polymerase chain reaction.

    Science.gov (United States)

    Baum, Paul D; Young, Jennifer J; Zhang, Qianjun; Kasakow, Zeljka; McCune, Joseph M

    2011-04-01

    Methods to measure the sequence diversity of polymerase chain reaction (PCR)-amplified DNA lack standards for use as assay calibrators and controls. Here we present a general and economical method for developing customizable DNA standards of known sequence diversity. Standards ranging from 1 to 25,000 sequences were generated by directional ligation of oligonucleotide "words" of standard length and GC content and then amplified by PCR. The sequence accuracy and diversity of the library were validated using AmpliCot analysis (DNA hybridization kinetics) and Illumina sequencing. The library has the following features: (i) pools containing tens of thousands of sequences can be generated from the ligation of relatively few commercially synthesized short oligonucleotides; (ii) each sequence differs from all others in the library at a minimum of three nucleotide positions, permitting discrimination between different sequences by either sequencing or hybridization; (iii) all sequences have identical length, GC content, and melting temperature; (iv) the identity of each standard can be verified by restriction digestion; and (v) once made, the ends of the library may be cleaved and replaced with sequences to match any PCR primer pair. These standards should greatly improve the accuracy and reproducibility of sequence diversity measurements.

  5. Transgenic Animal Mutation Assays

    Institute of Scientific and Technical Information of China (English)

    Tao Chen; Ph.D.D.A.B.T.

    2005-01-01

    @@ The novel transgenic mouse and rat mutation assays have provided a tool for analyzing in vivo mutation in any tissue, thus permitting the direct comparison of cancer incidence with mutant frequency.

  6. Tube-Forming Assays.

    Science.gov (United States)

    Brown, Ryan M; Meah, Christopher J; Heath, Victoria L; Styles, Iain B; Bicknell, Roy

    2016-01-01

    Angiogenesis involves the generation of new blood vessels from the existing vasculature and is dependent on many growth factors and signaling events. In vivo angiogenesis is dynamic and complex, meaning assays are commonly utilized to explore specific targets for research into this area. Tube-forming assays offer an excellent overview of the molecular processes in angiogenesis. The Matrigel tube forming assay is a simple-to-implement but powerful tool for identifying biomolecules involved in angiogenesis. A detailed experimental protocol on the implementation of the assay is described in conjunction with an in-depth review of methods that can be applied to the analysis of the tube formation. In addition, an ImageJ plug-in is presented which allows automatic quantification of tube images reducing analysis times while removing user bias and subjectivity.

  7. Cell viability assays: introduction.

    Science.gov (United States)

    Stoddart, Martin J

    2011-01-01

    The measurement of cell viability plays a fundamental role in all forms of cell culture. Sometimes it is the main purpose of the experiment, such as in toxicity assays. Alternatively, cell viability can be used to -correlate cell behaviour to cell number, providing a more accurate picture of, for example, anabolic -activity. There are wide arrays of cell viability methods which range from the most routine trypan blue dye exclusion assay to highly complex analysis of individual cells, such as using RAMAN microscopy. The cost, speed, and complexity of equipment required will all play a role in determining the assay used. This chapter aims to provide an overview of many of the assays available today.

  8. CMR Shuffler System: Passive Mode Calibration and Certification Report

    Energy Technology Data Exchange (ETDEWEB)

    Frame, Katherine C. [Los Alamos National Laboratory; Gomez, Cipriano D. [Retired CMR-OPS: OPERATIONS; Salazar, William R. [Los Alamos National Laboratory; Mayo, Douglas R. [Los Alamos National Laboratory; Vigil, Georgiana M. [Los Alamos National Laboratory; Crooks, William J. [Los Alamos National Laboratory; Stange, Sy [Los Alamos National Laboratory

    2012-07-20

    Los Alamos National Laboratory has a number of spherical confinement vessels (CVs) remaining from tests involving nuclear materials. These vessels have an inner diameter of 6 feet with 1 to 2 inch thick steel walls. The goal of the Confinement Vessel Disposition (CVD) project is to remove debris and reduce contamination inside the vessels. As debris is removed from the vessels, material will be placed in waste drums. Far-field gamma ray assay will be used to determine when a drum is nearing a {sup 239}Pu equivalent mass of less than 200 g. The drum will then be assayed using a waste drum shuffler operated in passive mode using a neutron coincidence counting method for accountability. This report focuses on the testing and calibration of the CMR waste drum shuffler in passive mode operation. Initial testing was performed to confirm previously accepted measurement parameters. The system was then calibrated using a set of weapons grade Pu (WGPu, {sup 239}Pu > 93%) oxide standards placed inside a 55 gallon drum. The calibration data ranges from Pu mass of 0.5 g to 188.9 g. The CMR waste drum shuffler has been tested and calibrated in passive mode in preparation for safeguards accountability measurements of waste drums containing material removed from CVs for the CVD project.

  9. New Rapid Spore Assay

    Science.gov (United States)

    Kminek, Gerhard; Conley, Catharine

    2012-07-01

    The presentation will detail approved Planetary Protection specifications for the Rapid Spore Assay for spacecraft components and subsystems. Outlined will be the research and studies on which the specifications were based. The research, funded by ESA and NASA/JPL, was conducted over a period of two years and was followed by limited cleanroom studies to assess the feasibility of this assay during spacecraft assembly.

  10. Mexican national pyronometer network calibration

    Science.gov (United States)

    VAldes, M.; Villarreal, L.; Estevez, H.; Riveros, D.

    2013-12-01

    In order to take advantage of the solar radiation as an alternate energy source it is necessary to evaluate the spatial and temporal availability. The Mexican National Meterological Service (SMN) has a network with 136 meteorological stations, each coupled with a pyronometer for measuring the global solar radiation. Some of these stations had not been calibrated in several years. The Mexican Department of Energy (SENER) in order to count on a reliable evaluation of the solar resource funded this project to calibrate the SMN pyrometer network and validate the data. The calibration of the 136 pyronometers by the intercomparison method recommended by the World Meterological Organization (WMO) requires lengthy observations and specific environmental conditions such as clear skies and a stable atmosphere, circumstances that determine the site and season of the calibration. The Solar Radiation Section of the Instituto de Geofísica of the Universidad Nacional Autónoma de México is a Regional Center of the WMO and is certified to carry out the calibration procedures and emit certificates. We are responsible for the recalibration of the pyronometer network of the SMN. A continuous emission solar simulator with exposed areas with 30cm diameters was acquired to reduce the calibration time and not depend on atmospheric conditions. We present the results of the calibration of 10 thermopile pyronometers and one photovoltaic cell by the intercomparison method with more than 10000 observations each and those obtained with the solar simulator.

  11. Jet energy calibration in ATLAS

    CERN Document Server

    Schouten, Doug

    A correct energy calibration for jets is essential to the success of the ATLAS experi- ment. In this thesis I study a method for deriving an in situ jet energy calibration for the ATLAS detector. In particular, I show the applicability of the missing transverse energy projection fraction method. This method is shown to set the correct mean energy for jets. Pileup effects due to the high luminosities at ATLAS are also stud- ied. I study the correlations in lateral distributions of pileup energy, as well as the luminosity dependence of the in situ calibration metho

  12. Calibrating System for Vacuum Gauges

    Institute of Scientific and Technical Information of China (English)

    MengJun; YangXiaotian; HaoBinggan; HouShengjun; HuZhenjun

    2003-01-01

    In order to measure the vacuum degree, a lot of vacuum gauges will be used in CSR vacuum system. We bought several types of vacuum gauges. We know that different typos of vacuum gauges or even one type of vacuum gauges have different measure results in same condition, so they must be calibrated. But it seems impossible for us to send so many gauges to the calibrating station outside because of the high price. So the best choice is to build a second class calibrating station for vacuum gauges by ourselves (Fig.l).

  13. Diversity's Calling

    Science.gov (United States)

    Cooper, Kenneth J.

    2011-01-01

    This article discusses how a Harvard-educated scholar of English and poetry, Dr. M. Lee Pelton puts a prominent face on changes that are underway at Boston's Emerson College. Faced with a public controversy over its limited faculty diversity, Emerson College has responded with a spate of hirings and promotions of minorities, capped by the…

  14. Generational diversity.

    Science.gov (United States)

    Kramer, Linda W

    2010-01-01

    Generational diversity has proven challenges for nurse leaders, and generational values may influence ideas about work and career planning. This article discusses generational gaps, influencing factors and support, and the various generational groups present in today's workplace as well as the consequences of need addressing these issues. The article ends with a discussion of possible solutions.

  15. Calibration of "Babyline" RP instruments

    CERN Multimedia

    2015-01-01

      If you have old RP instrumentation of the “Babyline” type, as shown in the photo, please contact the Radiation Protection Group (Joffrey Germa, 73171) to have the instrument checked and calibrated. Thank you. Radiation Protection Group

  16. Field calibration of cup anemometers

    Energy Technology Data Exchange (ETDEWEB)

    Kristensen, L.; Jensen, G.; Hansen, A.; Kirkegaard, P.

    2001-01-01

    An outdoor calibration facility for cup anemometers, where the signals from 10 anemometers of which at least one is a reference can be recorded simultaneously, has been established. The results are discussed with special emphasis on the statistical significance of the calibration expressions. It is concluded that the method has the advantage that many anemometers can be calibrated accurately with a minimum of work and cost. The obvious disadvantage is that the calibration of a set of anemometers may take more than one month in order to have wind speeds covering a sufficiently large magnitude range in a wind direction sector where we can be sure that the instruments are exposed to identical, simultaneous wind flows. Another main conclusion is that statistical uncertainty must be carefully evaluated since the individual 10 minute wind-speed averages are not statistically independent. (au)

  17. Lead Slowing-Down Spectrometry Time Spectral Analysis for Spent Fuel Assay: FY12 Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Kulisek, Jonathan A.; Anderson, Kevin K.; Casella, Andrew M.; Siciliano, Edward R.; Warren, Glen A.

    2012-09-28

    Executive Summary Developing a method for the accurate, direct, and independent assay of the fissile isotopes in bulk materials (such as used fuel) from next-generation domestic nuclear fuel cycles is a goal of the Office of Nuclear Energy, Fuel Cycle R&D, Material Protection and Control Technology (MPACT) Campaign. To meet this goal, MPACT supports a multi-institutional collaboration, of which PNNL is a part, to study the feasibility of Lead Slowing Down Spectroscopy (LSDS). This technique is an active nondestructive assay method that has the potential to provide independent, direct measurement of Pu and U isotopic masses in used fuel with an uncertainty considerably lower than the approximately 10% typical of today’s confirmatory methods. This document is a progress report for FY2012 PNNL analysis and algorithm development. Progress made by PNNL in FY2012 continues to indicate the promise of LSDS analysis and algorithms applied to used fuel assemblies. PNNL further refined the semi-empirical model developed in FY2011 based on singular value decomposition (SVD) to numerically account for the effects of self-shielding. The average uncertainty in the Pu mass across the NGSI-64 fuel assemblies was shown to be less than 3% using only six calibration assemblies with a 2% uncertainty in the isotopic masses. When calibrated against the six NGSI-64 fuel assemblies, the algorithm was able to determine the total Pu mass within <2% uncertainty for the 27 diversion cases also developed under NGSI. Two purely empirical algorithms were developed that do not require the use of Pu isotopic fission chambers. The semi-empirical and purely empirical algorithms were successfully tested using MCNPX simulations as well applied to experimental data measured by RPI using their LSDS. The algorithms were able to describe the 235U masses of the RPI measurements with an average uncertainty of 2.3%. Analyses were conducted that provided valuable insight with regard to design requirements (e

  18. Infrasound Sensor Calibration and Response

    Science.gov (United States)

    2012-09-01

    functions with faster rise times. SUMMARY We have documented past work on the determination of the calibration constant of the LANL infrasound sensor...Monitoring Technologies 735 Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collection of information is estimated...National Laboratory ( LANL ) has operated an infrasound sensor calibration chamber that operates over a frequency range of 0.02 to 4 Hz. This chamber has

  19. Bayesian Calibration of Microsimulation Models.

    Science.gov (United States)

    Rutter, Carolyn M; Miglioretti, Diana L; Savarino, James E

    2009-12-01

    Microsimulation models that describe disease processes synthesize information from multiple sources and can be used to estimate the effects of screening and treatment on cancer incidence and mortality at a population level. These models are characterized by simulation of individual event histories for an idealized population of interest. Microsimulation models are complex and invariably include parameters that are not well informed by existing data. Therefore, a key component of model development is the choice of parameter values. Microsimulation model parameter values are selected to reproduce expected or known results though the process of model calibration. Calibration may be done by perturbing model parameters one at a time or by using a search algorithm. As an alternative, we propose a Bayesian method to calibrate microsimulation models that uses Markov chain Monte Carlo. We show that this approach converges to the target distribution and use a simulation study to demonstrate its finite-sample performance. Although computationally intensive, this approach has several advantages over previously proposed methods, including the use of statistical criteria to select parameter values, simultaneous calibration of multiple parameters to multiple data sources, incorporation of information via prior distributions, description of parameter identifiability, and the ability to obtain interval estimates of model parameters. We develop a microsimulation model for colorectal cancer and use our proposed method to calibrate model parameters. The microsimulation model provides a good fit to the calibration data. We find evidence that some parameters are identified primarily through prior distributions. Our results underscore the need to incorporate multiple sources of variability (i.e., due to calibration data, unknown parameters, and estimated parameters and predicted values) when calibrating and applying microsimulation models.

  20. Pressures Detector Calibration and Measurement

    CERN Document Server

    AUTHOR|(CDS)2156315

    2016-01-01

    This is report of my first and second projects (of 3) in NA61. I did data taking and analysis in order to do calibration of pressure detectors and verified it. I analyzed the data by ROOT software using the C ++ programming language. The first part of my project was determination of calibration factor of pressure sensors. Based on that result, I examined the relation between pressure drop, gas flow rate of in paper filter and its diameter.

  1. Beam Imaging and Luminosity Calibration

    CERN Document Server

    Klute, Markus; Salfeld-Nebgen, Jakob

    2016-01-01

    We discuss a method to reconstruct two-dimensional proton bunch densities using vertex distributions accumulated during LHC beam-beam scans. The $x$-$y$ correlations in the beam shapes are studied and an alternative luminosity calibration technique is introduced. We demonstrate the method on simulated beam-beam scans and estimate the uncertainty on the luminosity calibration associated to the beam-shape reconstruction to be below 1\\%.

  2. Computer-determined assay time based on preset precision

    Energy Technology Data Exchange (ETDEWEB)

    Foster, L.A.; Hagan, R.; Martin, E.R.; Wachter, J.R.; Bonner, C.A.; Malcom, J.E. [Los Alamos National Lab., NM (United States). Nuclear Materials Measurement and Accountability

    1994-08-01

    Most current assay systems for special nuclear materials (SNM) operate on the principle of a fixed assay time which provides acceptable measurement precision without sacrificing the required throughput of the instrument. Waste items to be assayed for SNM content can contain a wide range of nuclear material. Counting all items for the same preset assay time results in a wide range of measurement precision and wastes time at the upper end of the calibration range. A short time sample taken at the beginning of the assay could optimize the analysis time on the basis of the required measurement precision. To illustrate the technique of automatically determining the assay time, measurements were made with a segmented gamma scanner at the Plutonium Facility of Los Alamos National Laboratory with the assay time for each segment determined by counting statistics in that segment. Segments with very little SNM were quickly determined to be below the lower limit of the measurement range and the measurement was stopped. Segments with significant SNM were optimally assays to the preset precision. With this method the total assay time for each item is determined by the desired preset precision. This report describes the precision-based algorithm and presents the results of measurements made to test its validity.

  3. Against vaccine assay secrecy.

    Science.gov (United States)

    Herder, Matthew; Hatchette, Todd F; Halperin, Scott A; Langley, Joanne M

    2015-01-01

    Increasing the transparency of the evidence base behind health interventions such as pharmaceuticals, biologics, and medical devices, has become a major point of critique, conflict, and policy focus in recent years. Yet the lack of publicly available information regarding the immunogenicity assays upon which many important, widely used vaccines are based has received no attention to date. In this paper we draw attention to this critical public health problem by reporting on our efforts to secure vaccine assay information in respect of 10 vaccines through Canada's access to information law. We argue, under Canadian law, that the public health interest in having access to the methods for these laboratory procedures should override claims by vaccine manufacturers and regulators that this information is proprietary; and, we call upon several actors to take steps to ensure greater transparency with respect to vaccine assays, including regulators, private firms, researchers, research institutions, research funders, and journal editors.

  4. Against vaccine assay secrecy

    Science.gov (United States)

    Herder, Matthew; Hatchette, Todd F; Halperin, Scott A; Langley, Joanne M

    2015-01-01

    Increasing the transparency of the evidence base behind health interventions such as pharmaceuticals, biologics, and medical devices, has become a major point of critique, conflict, and policy focus in recent years. Yet the lack of publicly available information regarding the immunogenicity assays upon which many important, widely used vaccines are based has received no attention to date. In this paper we draw attention to this critical public health problem by reporting on our efforts to secure vaccine assay information in respect of 10 vaccines through Canada's access to information law. We argue, under Canadian law, that the public health interest in having access to the methods for these laboratory procedures should override claims by vaccine manufacturers and regulators that this information is proprietary; and, we call upon several actors to take steps to ensure greater transparency with respect to vaccine assays, including regulators, private firms, researchers, research institutions, research funders, and journal editors. PMID:25826194

  5. Incompatible Ages for Clearwing Butterflies Based on Alternative Secondary Calibrations.

    Science.gov (United States)

    Garzón-Orduña, Ivonne J; Silva-Brandão, Karina L; Willmott, Keith R; Freitas, André V L; Brower, Andrew V Z

    2015-09-01

    The recent publication of a time-tree for the plant family Solanaceae (nightshades) provides the opportunity to use independent calibrations to test divergence times previously inferred for the diverse Neotropical butterfly tribe Ithomiini. Ithomiini includes clades that are obligate herbivores of Solanaceae, with some genera feeding on only one genus. We used 8 calibrations extracted from the plant tree in a new relaxed molecular-clock analysis to produce an alternative temporal framework for the diversification of ithomiines. We compared the resulting age estimates to: (i) a time-tree obtained using 7 secondary calibrations from the Nymphalidae tree of Wahlberg et al. (2009), and (ii) Wahlberg et al.'s (2009) original age estimates for the same clades. We found that Bayesian clock estimates were rather sensitive to a variety of analytical parameters, including taxon sampling. Regardless of this sensitivity however, ithomiine divergence times calibrated with the ages of nightshades were always on average half the age of previous estimates. Younger dates for ithomiine clades appear to fit better with factors long suggested to have promoted diversification of the group such as the uplifting of the Andes, in the case of montane genera. Alternatively, if ithomiines are as old as previous estimates suggest, the recent ages inferred for the diversification of Solanaceae seem likely to be seriously underestimated. Our study exemplifies the difficulty of testing hypotheses of divergence times and of choosing between alternative dating scenarios, and shows that age estimates based on seemingly plausible calibrations may be grossly incongruent.

  6. Assays for calcitonin receptors

    Energy Technology Data Exchange (ETDEWEB)

    Teitelbaum, A.P.; Nissenson, R.A.; Arnaud, C.D.

    1985-01-01

    The assays for calcitonin receptors described focus on their use in the study of the well-established target organs for calcitonin, bone and kidney. The radioligand used in virtually all calcitonin binding studies is /sup 125/I-labelled salmon calcitonin. The lack of methionine residues in this peptide permits the use of chloramine-T for the iodination reaction. Binding assays are described for intact bone, skeletal plasma membranes, renal plasma membranes, and primary kidney cell cultures of rats. Studies on calcitonin metabolism in laboratory animals and regulation of calcitonin receptors are reviewed.

  7. CTL ELISPOT assay.

    Science.gov (United States)

    Ranieri, Elena; Popescu, Iulia; Gigante, Margherita

    2014-01-01

    Enzyme-linked immune absorbent spot (Elispot) is a quantitative method for measuring relevant parameters of T cell activation. The sensitivity of Elispot allows the detection of low-frequency antigen-specific T cells that secrete cytokines and effector molecules, such as granzyme B and perforin. Cytotoxic T cell (CTL) studies have taken advantage with this high-throughput technology by providing insights into quantity and immune kinetics. Accuracy, sensitivity, reproducibility, and robustness of Elispot resulted in a wide range of applications in research as well as in diagnostic field. Actually, CTL monitoring by Elispot is a gold standard for the evaluation of antigen-specific T cell immunity in clinical trials and vaccine candidates where the ability to detect rare antigen-specific T cells is of relevance for immune diagnostic. The most utilized Elispot assay is the interferon-gamma (IFN-γ) test, a marker for CD8(+) CTL activation, but Elispot can also be used to distinguish different subsets of activated T cells by using other cytokines such as T-helper (Th) 1-type cells (characterized by the production of IFN-γ, IL-2, IL-6, IL-12, IL-21, and TNF-α), Th2 (producing cytokines like IL-4, IL-5, IL-10, and IL-13), and Th17 (IL-17) cells. The reliability of Elispot-generated data, by the evaluation of T cell frequency recognizing individual antigen/peptide, is the core of this method currently applied widely to investigate specific immune responses in cancer, infections, allergies, and autoimmune diseases. The Elispot assay is competing with other methods measuring single-cell cytokine production, e.g., intracellular cytokine by FACS or Miltenyi cytokine secretion assay. Other types of lymphocyte frequency and function assays include limiting dilution assay (LDA), cytotoxic T cell assay (CTL), and tetramer staining. Compared with respect to sensitivity the Elispot assay is outranking other methods to define frequency of antigen-specific lymphocytes. The method

  8. Troubling Diversity?

    DEFF Research Database (Denmark)

    Jæger, Kirsten; Jensen, Annie Aarup

    2009-01-01

    Focussing on the cultural encounter between nurses and ethnic minority patients in Danish hospitals, this paper presents the results of a comprehensive analysis of nursing discourses on cultural difference and intercultural contact. Articles from the Danish professional journal ‘The Nurse......', published in the period from 2000 to 2008, pertaining to cultural contact and intercultural understanding have been analyzed in order to uncover nurses' experience of ethnic and cultural diversity and the ways, in which these experiences challenge their cultural and professional expertise. Results...... are related to recent contributions to diversity management theory and intercultural communication theory, calling for a strengthened focus on the historical, political, and social dimensions of intercultural contact. In continuation of these trends, an alternative, theoretical framework...

  9. Doing Diversity

    DEFF Research Database (Denmark)

    Just, Sine Nørholm; Christiansen, Tanja Juul

    2012-01-01

    Questions of agency in text–audience relations are less studied than other aspects of rhetorical agency. We suggest conceptualizing and analyzing the relationship between texts and audiences from the perspective of performativity, as it has been developed by Judith Butler. Thus, we argue that tex...... demonstrate the explanatory potential of the performative framework. Subsequently, we discuss how the concept of personae may provide a basis for alternatives to the restrictive positioning that currently dominates diversity management rhetoric....

  10. Teaching Diversity

    OpenAIRE

    Kay Young McChesney

    2015-01-01

    This article is targeted to faculty teaching race and ethnicity, racism, diversity, and multicultural courses. Many students equate race with skin color. The premise of this article is that to teach students about the social construction of race, teachers must first know enough science to teach students that race is not biological. This article examines the biology of race by showing how advances in DNA sequencing led ...

  11. A comprehensive company database analysis of biological assay variability.

    Science.gov (United States)

    Kramer, Christian; Dahl, Göran; Tyrchan, Christian; Ulander, Johan

    2016-08-01

    Analysis of data from various compounds measured in diverse biological assays is a central part of drug discovery research projects. However, no systematic overview of the variability in biological assays has been published and judgments on assay quality and robustness of data are often based on personal belief and experience within the drug discovery community. To address this we performed a reproducibility analysis of all biological assays at AstraZeneca between 2005 and 2014. We found an average experimental uncertainty of less than a twofold difference and no technologies or assay types had higher variability than others. This work suggests that robust data can be obtained from the most commonly applied biological assays.

  12. Instrument for assaying radiation

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, Jody Rustyn; Farfan, Eduardo B.

    2016-03-22

    An instrument for assaying radiation includes a flat panel detector having a first side opposed to a second side. A collimated aperture covers at least a portion of the first side of the flat panel detector. At least one of a display screen or a radiation shield may cover at least a portion of the second side of the flat panel detector.

  13. New oligosaccharyltransferase assay method.

    Science.gov (United States)

    Kohda, Daisuke; Yamada, Masaki; Igura, Mayumi; Kamishikiryo, Jun; Maenaka, Katsumi

    2007-11-01

    We developed a new in vitro assay for oligosaccharyltransferase (OST), which catalyzes the transfer of preassembled oligosaccharides on lipid carriers onto asparagine residues in polypeptide chains. The asparagine residues reside in the sequon, Asn-X-Thr/Ser, where X can be any amino acid residue except Pro. We demonstrate the potency of our assay using the OST from yeast. In our method, polyacrylamide gel electrophoresis is used to separate the glycopeptide products from the peptide substrates. The substrate peptide is fluorescently labeled and the formation of glycopeptides is analyzed by fluorescence gel imaging. Two in vitro OST assay methods are now widely used, but both the methods depend on previous knowledge of the oligosaccharide moiety: One method uses lectin binding as the separation mechanism and the other method uses biosynthetically or chemoenzymatically synthesized lipid-linked oligosaccharides as donors. N-linked protein glycosylation is found in all three domains of life, but little is known about the N-glycosylation in Archaea. Thus, our new assay, which does not require a priori knowledge of the oligosaccharides, will be useful in such cases. Indeed, we have detected the OST activity in the membrane fraction from a hyperthermophilic archaeon, Pyrococcus furiosus.

  14. Hyaluronic Acid Assays

    DEFF Research Database (Denmark)

    Itenov, Theis S; Kirkby, Nikolai S; Bestle, Morten H

    2015-01-01

    BACKGROUD: Hyaluronic acid (HA) is proposed as a marker of functional liver capacity. The aim of the present study was to compare a new turbidimetric assay for measuring HA with the current standard method. METHODS: HA was measured by a particle-enhanced turbidimetric immunoassay (PETIA) and enzyme...

  15. Mathematical calibration of Ge detectors, and the instruments that use them

    Energy Technology Data Exchange (ETDEWEB)

    Bronson, F.L.; Young, B. [Canberra Industries, Meriden, CT (United States)

    1997-11-01

    Efficiency calibrations for Ge detectors are typically done with the use of multiple energy calibrations sources which are added to a bulk matrix intended to simulate the measurement sample, and then deposited in the sample container. This is rather easy for common laboratory samples. Bu, even there, for many environmental samples, waste assay samples, and operational health physics samples, accurate calibrations are difficult. For these situations, various mathematical corrections or direct calibration techniques are used at Canberra. EML has pioneered the use of mathematical calibrations following source-based detector characterization measurements for in situ measurements of environmental fallout. Canberra has expanded this by the use of MCNP for the source measurements required in EML. For other calibration situations, MCNP was used directly, as the primary calibration method. This is demonstrated to be at least as accurate as source based measurements, and probably better. Recently, a new method [ISOCS] has been developed and is nearing completion. This promises to be an easy to use calibration software that can be used by the customer for in situ gamma spectroscopy to accurately measure many large sized samples, such as boxes, drums, pipes, or to calibrate small laboratory-type samples. 8 refs., 8 figs., 5 tabs.

  16. General Calibration Algorithm for Single-transmitting-dual-receiving Polarimetric SAR System

    Directory of Open Access Journals (Sweden)

    Chen Lin

    2012-09-01

    Full Text Available The single-transmitting-dual-receiving polarimetric SAR system has only two receving channels, which induces lack of prior information for calibration. Due to the polarization diversity of this kind of system (which operates on different dual and compact polarimetric modes, there has not a general algorithm currently. In this paper, a new general calibration algorithm is proposed for single-transmitting-dual-receiving polarimetric SAR system, which can be widely applied to diverse polarization modes. The transmitting and receiving distortion can be estimated using trihedral, 0° dihedral and 45° dihedral as ideal point targets without any assumption on the scene and system. The basic principle of this new algorithm is induced theoretically. The effect of calibrator error on the distortion estimation is analyzed by simulation. Point targets’calibration results and polarization signatures verify this algorithm.

  17. Collaborative study for the calibration of a replacement International Standard for Tetanus Toxoid Adsorbed.

    Science.gov (United States)

    Tierney, Rob; Stickings, Paul; Hockley, Jason; Rigsby, Peter; Iwaki, Masaaki; Sesardic, Dorothea

    2011-11-01

    We present the results of a collaborative study for the establishment of a replacement International Standard (IS) for Tetanus Toxoid Adsorbed. Two candidate preparations were included in the study, one of which was established as the 4th IS for Tetanus Toxoid Adsorbed at the WHO Expert Committee on Biological Standardization meeting in October 2010. This preparation was found to have a unitage of 490 IU/ampoule, based on calibration in guinea pig challenge assays. Results from mouse challenge assays suggest that the relative performance of two candidate preparations may differ significantly between guinea pigs and mice. The authors note that the number of laboratories that performed guinea pig challenge assays, which are used to calibrate and assign IU, is much lower than in previous collaborative studies and this may have implications for calibration of replacement standards in the future. The issue of assigning separate units to the IS for guinea pig and mouse assays is discussed. The study also assessed performance of the replacement standard in serological assays which are used as alternative procedures to challenge assays for tetanus potency testing. Results suggest that the replacement standard is suitable for use as the reference vaccine in serological assays.

  18. The KLOE Online Calibration System

    Institute of Scientific and Technical Information of China (English)

    E.Pasqualucci

    2001-01-01

    Based on all the features of the KLOE online software,the online calibration system performs current calibration quality checking in real time and starts automatically new calibration procedures when needed.Acalibration manager process controls the system,implementing the interface to the online system,receiving information from the run control and translating its state transitions to a separate state machine.It acts as a " calibration run controller"and performs failure recovery when requested by a set of process checkers.The core of the system is a multi-threaded OO histogram server that receives histogramming commands by remote processes and operates on local ROOT histograms.A client library and C,fortran and C++ application interface libraries allow the user to connect and define his own histogram or read histograms owned by others using an bool-like interface.Several calibration processes running in parallel in a destributed,multiplatform environment can fill the same histograms,allowing fast external information check.A monitor thread allow remote browsing for visual inspection,Pre-filtered data are read in nonprivileged spy mode from the data acquisition system via the Kloe Integrated Dataflow,privileged spy mode from the data acquisiton system via the Kole Integrated Dataflow.The main characteristics of the system are presented.

  19. Diverse Multilateralism

    DEFF Research Database (Denmark)

    Wuthnow, Joel; Li, Xin; Qi, Lingling

    2012-01-01

    This article addresses Chinas multilateral diplomacy by identifying four distinct strategies: watching, engaging, circumventing, and shaping. The typology builds on two literatures: power transition theory, and the more recent “assertiveness” discourse in the West. Drawing from a range of cases...... in both the economic and security domains, the article argues that China’s multilateralism is diverse, and that it cannot be un-problematically characterized as either status-quo or revisionist in nature. However, the general trend appears to be towards engagement, but with an assertive tact as China...

  20. Exposing diversity

    DEFF Research Database (Denmark)

    Nørtoft, Kamilla; Nordentoft, Helle Merete

    . A prominent research theme in health care studies is, therefore, to explicate the gap between theory and practice. The question this paper addresses is how a learning environment can be designed to bridge this theory-practice gap, expose the differences in situated interactions and qualify health...... in the homes of older people and in pedagogical institutions targeting older people. In the paper we look at the potentials and challenges in working with ethnographic video narratives as a pedagogical tool. Our findings indicate that the use of video narratives has the potential to expose the diversity...

  1. Reliability-Based Code Calibration

    DEFF Research Database (Denmark)

    Faber, M.H.; Sørensen, John Dalsgaard

    2003-01-01

    The present paper addresses fundamental concepts of reliability based code calibration. First basic principles of structural reliability theory are introduced and it is shown how the results of FORM based reliability analysis may be related to partial safety factors and characteristic values....... Thereafter the code calibration problem is presented in its principal decision theoretical form and it is discussed how acceptable levels of failure probability (or target reliabilities) may be established. Furthermore suggested values for acceptable annual failure probabilities are given for ultimate...... and serviceability limit states. Finally the paper describes the Joint Committee on Structural Safety (JCSS) recommended procedure - CodeCal - for the practical implementation of reliability based code calibration of LRFD based design codes....

  2. Astrid-2 EMMA Magnetic Calibration

    DEFF Research Database (Denmark)

    Merayo, José M.G.; Brauer, Peter; Risbo, Torben

    1998-01-01

    The Swedish micro-satellite Astrid-2 contains a tri-axial fluxgate magnetometer with the sensor co-located with a Technical University of Denmark (DTU) star camera for absolute attitude, and extended about 0.9 m on a hinged boom. The magnetometer is part of the RIT EMMA electric and magnetic fields...... Survey of Sweden near Stockholm on the night of May 15.-16., 1997. The magnetic calibration and the intercalibration between the star camera and the magnetic sensor was performed by measuring the Earth's magnetic field and simultaneously observing the star sky with the camera. The rotation matrix between...... fit calibration parameters. Owing to time shortage, we did not evaluate the temperature coefficients of the flight sensor calibration parameters. However, this was done for an identical flight spare magnetometer sensor at the magnetic coil facility belonging to the Technical University of Braunschweig...

  3. On chromatic and geometrical calibration

    DEFF Research Database (Denmark)

    Folm-Hansen, Jørgen

    1999-01-01

    of non-uniformity of the illumination of the image plane. Only the image deforming aberrations and the non-uniformity of illumination are included in the calibration models. The topics of the pinhole camera model and the extension to the Direct Linear Transform (DLT) are described. It is shown how......The main subject of the present thesis is different methods for the geometrical and chromatic calibration of cameras in various environments. For the monochromatic issues of the calibration we present the acquisition of monochrome images, the classic monochrome aberrations and the various sources...... the DLT can be extended with non-linear models of the common lens aberrations/errors some of them caused by manufacturing defects like decentering and thin prism distortion. The relation between a warping and the non-linear defects are shown. The issue of making a good resampling of an image by using...

  4. Flexible calibration procedure for fringe projection profilometry

    OpenAIRE

    Vargas, Javier; Quiroga Mellado, Juan Antonio; Terrón López, María José

    2007-01-01

    A novel calibration method for whole field three-dimensional shape measurement by means of fringe projection is presented. Standard calibration techniques, polynomial-and model-based, have practical limitations such as the difficulty of measuring large fields of view, the need to use precise z stages, and bad calibration results due to inaccurate calibration points. The proposed calibration procedure is a mixture of the two main standard techniques, sharing their benefits and avoiding their m...

  5. Improving quantitative precision and throughput by reducing calibrator use in liquid chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Rule, Geoffrey S., E-mail: geoffrey.s.rule@aruplab.com [ARUP Institute for Clinical and Experimental Pathology, 500 Chipeta Way, Salt Lake City, UT 84108 (United States); Rockwood, Alan L. [ARUP Institute for Clinical and Experimental Pathology, 500 Chipeta Way, Salt Lake City, UT 84108 (United States); Department of Pathology, University of Utah School of Medicine, 2100 Jones Medical Research Bldg., Salt Lake City, UT 84132 (United States)

    2016-05-05

    To improve efficiency in our mass spectrometry laboratories we have made efforts to reduce the number of calibration standards utilized for quantitation over time. We often analyze three or more batches of 96 samples per day, on a single instrument, for a number of assays. With a conventional calibration scheme at six concentration levels this amounts to more than 5000 calibration points per year. Modern LC-tandem mass spectrometric instrumentation is extremely rugged however, and isotopically labelled internal standards are widely available. This made us consider whether alternative calibration strategies could be utilized to reduce the number of calibration standards analyzed while still retaining high precision and accurate quantitation. Here we demonstrate how, by utilizing a single calibration point in each sample batch, and using the resulting response factor (RF) to update an existing, historical response factor (HRF), we are able to obtain improved precision over a conventional multipoint calibration approach, as judged by quality control samples. The laboratory component of this study was conducted with an existing LC tandem mass spectrometric method for three androgen analytes in our production laboratory. Using examples from both simulated and laboratory data we illustrate several aspects of our single point alternative calibration strategy and compare it with a conventional, multipoint calibration approach. We conclude that both the cost and burden of preparing multiple calibration standards with every batch of samples can be reduced while at the same time maintaining, or even improving, analytical quality. - Highlights: • Use of a weighted single point calibration approach improves quantitative precision. • A weighted response factor approach incorporates historical calibration information. • Several scenarios are discussed with regard to their influence on quantitation.

  6. Non-Destructive Assay of Curium Contaminated Transuranic Waste Drums

    Energy Technology Data Exchange (ETDEWEB)

    Foster, L.A.

    1998-11-01

    At the Plutonium Facility at Los Alamos National Laboratory, a series of non-destructive assays were performed on five transuranic waste (TRU) drums containing non-plutonium scrap metal that was potentially contaminated with weapons grade plutonium and trace quantities of curium. Typically, waste drums containing metal matrices are assayed for plutonium content using passive neutron coincidence counting techniques. The presence of trace quantities of Cm-244 prevents this type of analysis because of the strong coincidence signal created by spontaneous fission of Cm-244. To discriminate between the plutonium and curium materials present, an active neutron measurement technique was used. A Cf shuffler designed for measurement of uranium bearing materials was calibrated for plutonium in the active mode. The waste drums were then assayed for plutonium content in the shuffler using the active-mode calibration. The curium contamination levels were estimated from the difference between the active-mode measurement in the shuffler and a passive assay in a neutron coincidence counter. Far field gamma-ray measurements were made to identify additional radioactive contaminants and to corroborate the plutonium measurement results obtained from the active-mode assay. This report describes in detail the measurement process used for characterization of these waste drums. The measurement results and the estimated uncertainty will be presented.

  7. Tank calibration; Arqueacao de tanques

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Ana [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

    2003-07-01

    This work relates the analysis of the norms ISO (International Organization for Standardization) for calibration of vertical cylindrical tanks used in fiscal measurement, established on Joint Regulation no 1 of June 19, 2000 between the ANP (National Agency of Petroleum) and the INMETRO (National Institute of Metrology, Normalization and Industrial Quality). In this work a comparison between norms ISO and norms published by the API (American Petroleum Institute) and the IP (Institute of Petroleum) up to 2001 was made. It was concluded that norms ISO are wider than norms API, IP, and INMETRO methods in the calibration of vertical cylindrical tanks. (author)

  8. Instrument Calibration and Certification Procedure

    Energy Technology Data Exchange (ETDEWEB)

    Davis, R. Wesley [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-05-31

    The Amptec 640SL-2 is a 4-wire Kelvin failsafe resistance meter, designed to reliably use very low-test currents for its resistance measurements. The 640SL-1 is a 2-wire version, designed to support customers using the Reynolds Industries type 311 connector. For both versions, a passive (analog) dual function DC Milliameter/Voltmeter allows the user to verify the actual 640SL output current level and the open circuit voltage on the test leads. This procedure includes tests of essential performance parameters. Any malfunction noticed during calibration, whether specifically tested for or not, shall be corrected before calibration continues or is completed.

  9. Performance standard for dose Calibrator

    CERN Document Server

    Darmawati, S

    2002-01-01

    Dose calibrator is an instrument used in hospitals to determine the activity of radionuclide for nuclear medicine purposes. International Electrotechnical Commission (IEC) has published IEC 1303:1994 standard that can be used as guidance to test the performance of the instrument. This paper briefly describes content of the document,as well as explains the assessment that had been carried out to test the instrument accuracy in Indonesia through intercomparison measurement.Its is suggested that hospitals acquire a medical physicist to perform the test for its dose calibrator. The need for performance standard in the form of Indonesia Standard is also touched.

  10. Kinetic Tetrazolium Microtiter Assay

    Science.gov (United States)

    Pierson, Duane L.; Stowe, Raymond; Koenig, David

    1993-01-01

    Kinetic tetrazolium microtiter assay (KTMA) involves use of tetrazolium salts and Triton X-100 (or equivalent), nontoxic, in vitro color developer solubilizing colored metabolite formazan without injuring or killing metabolizing cells. Provides for continuous measurement of metabolism and makes possible to determine rate of action of antimicrobial agent in real time as well as determines effective inhibitory concentrations. Used to monitor growth after addition of stimulatory compounds. Provides for kinetic determination of efficacy of biocide, greatly increasing reliability and precision of results. Also used to determine relative effectiveness of antimicrobial agent as function of time. Capability of generating results on day of test extremely important in treatment of water and waste, disinfection of hospital rooms, and in pharmaceutical, agricultural, and food-processing industries. Assay also used in many aspects of cell biology.

  11. The corneal pocket assay.

    Science.gov (United States)

    Ziche, Marina; Morbidelli, Lucia

    2015-01-01

    The cornea in most species is physiologically avascular, and thus this assay allows the measurement of newly formed vessels. The continuous monitoring of neovascular growth in the same animal allows the evaluation of drugs acting as suppressors or stimulators of angiogenesis. Under anesthesia a micropocket is produced in the cornea thickness and the angiogenesis stimulus (tumor tissue, cell suspension, growth factor) is placed into the pocket in order to induce vascular outgrowth from the limbal capillaries. Neovascular development and progression can be modified by the presence of locally released or applied inhibitory factors or by systemic treatments. In this chapter the experimental details of the avascular cornea assay, the technical challenges, and advantages and disadvantages in different species are discussed. Protocols for local drug treatment and tissue sampling for histology and pharmacokinetic profile are reported.

  12. B cell helper assays.

    Science.gov (United States)

    Abrignani, Sergio; Tonti, Elena; Casorati, Giulia; Dellabona, Paolo

    2009-01-01

    Activation, proliferation and differentiation of naïve B lymphocytes into memory B cells and plasma cells requires engagement of the B cell receptor (BCR) coupled to T-cell help (1, 2). T cells deliver help in cognate fashion when they are activated upon recognition of specific MHC-peptide complexes presented by B cells. T cells can also deliver help in a non-cognate or bystander fashion, when they do not find specific MHC-peptide complexes on B cells and are activated by alternative mechanisms. T-cell dependent activation of B cells can be studied in vitro by experimental models called "B cell helper assays" that are based on the co-culture of B cells with activated T cells. These assays allow to decipher the molecular bases for productive T-dependent B cell responses. We show here examples of B cell helper assays in vitro, which can be reproduced with any subset of T lymphocytes that displays the appropriate helper signals.

  13. Specific and global coagulation assays in the diagnosis of discrepant mild hemophilia A.

    Science.gov (United States)

    Bowyer, Annette E; Van Veen, Joost J; Goodeve, Anne C; Kitchen, Steve; Makris, Michael

    2013-12-01

    The activity of the factor VIII coagulation protein can be measured by three methods: a one or two-stage clotting assay and a chromogenic assay. The factor VIII activity of most individuals with mild hemophilia A is the same regardless of which method is employed. However, approximately 30% of patients show marked discrepancies in factor VIII activity measured with the different methods. The objective of this study was to investigate the incidence of assay discrepancy in our center, assess the impact of alternative reagents on factor VIII activity assays and determine the usefulness of global assays of hemostasis in mild hemophilia A. Factor VIII activity was measured in 84 individuals with mild hemophilia A using different reagents. Assay discrepancy was defined as a two-fold or greater difference between the results of the one-stage and two-stage clotting assays. Rotational thromboelastometry and calibrated automated thrombography were performed. Assay discrepancy was observed in 31% of individuals; 12% with lower activity in the two-stage assay and 19% with lower activity in the one-stage assay. The phenotype could not always be predicted from the individual's genotype. Chromogenic assays were shown to be a suitable alternative to the two-stage clotting assay. Thromboelastometry was found to have poor sensitivity in hemophilia. Calibrated automated thrombography supported the results obtained by the two-stage and chromogenic assays. The current international guidelines do not define the type of assay to be used in the diagnosis of mild hemophilia A and some patients could be misclassified as normal. In our study, 4% of patients would not have been diagnosed on the basis of the one-stage factor VIII assay. Laboratories should use both one stage and chromogenic (or two-stage) assays in the diagnosis of patients with possible hemophilia A.

  14. Fast facility spent-fuel and waste assay instrument. [Fluorinel Dissolution and Fuel Storage (FAST) Facility

    Energy Technology Data Exchange (ETDEWEB)

    Eccleston, G.W.; Johnson, S.S.; Menlove, H.O.; Van Lyssel, T.; Black, D.; Carlson, B.; Decker, L.; Echo, M.W.

    1983-01-01

    A delayed-neutron assay instrument was installed in the Fluorinel Dissolution and Fuel Storage Facility at Idaho National Engineering Laboratory. The dual-assay instrument is designed to measure both spent fuel and waste solids that are produced from fuel processing. A set of waste standards, fabricated by Los Alamos using uranium supplied by Exxon Nuclear Idaho Company, was used to calibrate the small-sample assay region of the instrument. Performance testing was completed before installation of the instrument to determine the effects of uranium enrichment, hydrogenous materials, and neutron poisons on assays. The unit was designed to measure high-enriched uranium samples in the presence of large neutron backgrounds. Measurements indicate that the system can assay low-enriched uranium samples with moderate backgrounds if calibrated with proper standards.

  15. Diversity Measures

    Directory of Open Access Journals (Sweden)

    MSc. Mentor Ademaj

    2012-06-01

    Full Text Available Diversity measures are a type of non-criminal measures foreseen in the Chapter IV of the Code of Juvenile Justice, which may be imposed on juvenile perpetrators of criminal acts. These measures can be applied in cases of minor offenses, for which is foreseen the criminal sanction with a fine or imprisonment up to three years or for criminal offenses committed by negligence for which is foreseen the sentence up to five years of imprisonment, except those cases that result in death. With the imposition of these measures is intended to prevent criminal proceedings against juveniles whenever is possible, rehabilitation and reintegration of juvenile in his/her community and the prevention of recidivist behaviour. Competent authority to impose them is the public prosecutor, the juvenile judge and juvenile court. And they are executed by the Kosovo Correctional Service.

  16. Optimizing diversity

    CERN Document Server

    Frein, Yannick; Sebo, Andras

    2007-01-01

    We consider the problem of minimizing the size of a family of sets G such that every subset of 1,...,n can be written as a disjoint union of at most k members of G, where k and n are given numbers. This problem originates in a real-world application aiming at the diversity of industrial production. At the same time, the minimum of G so that every subset of 1,...,n is the union of two sets in G has been asked by Erdos and studied recently by Furedi and Katona without requiring the disjointness of the sets. A simple construction providing a feasible solution is conjectured to be optimal for this problem for all values of n and k and regardless of the disjointness requirement; we prove this conjecture in special cases including all (n,k) for which n <= 3k holds, and some individual values of n and k.

  17. Advances in Assays and Analytical Approaches for Botulinum Toxin Detection

    Energy Technology Data Exchange (ETDEWEB)

    Grate, Jay W.; Ozanich, Richard M.; Warner, Marvin G.; Bruckner-Lea, Cindy J.; Marks, James D.

    2010-08-04

    Methods to detect botulinum toxin, the most poisonous substance known, are reviewed. Current assays are being developed with two main objectives in mind: 1) to obtain sufficiently low detection limits to replace the mouse bioassay with an in vitro assay, and 2) to develop rapid assays for screening purposes that are as sensitive as possible while requiring an hour or less to process the sample an obtain the result. This review emphasizes the diverse analytical approaches and devices that have been developed over the last decade, while also briefly reviewing representative older immunoassays to provide background and context.

  18. Scalar Calibration of Vector Magnetometers

    DEFF Research Database (Denmark)

    Merayo, José M.G.; Brauer, Peter; Primdahl, Fritz;

    2000-01-01

    The calibration parameters of a vector magnetometer are estimated only by the use of a scalar reference magnetometer. The method presented in this paper differs from those previously reported in its linearized parametrization. This allows the determination of three offsets or signals in the absence...

  19. Measurement System and Calibration report

    DEFF Research Database (Denmark)

    Gómez Arranz, Paula; Villanueva, Héctor

    This Measurement System & Calibration report is describing DTU’s measurement system installed at a specific wind turbine. A major part of the sensors has been installed by others (see [1]) the rest of the sensors have been installed by DTU. The results of the measurements, described in this repor...

  20. Practical intraoperative stereo camera calibration.

    Science.gov (United States)

    Pratt, Philip; Bergeles, Christos; Darzi, Ara; Yang, Guang-Zhong

    2014-01-01

    Many of the currently available stereo endoscopes employed during minimally invasive surgical procedures have shallow depths of field. Consequently, focus settings are adjusted from time to time in order to achieve the best view of the operative workspace. Invalidating any prior calibration procedure, this presents a significant problem for image guidance applications as they typically rely on the calibrated camera parameters for a variety of geometric tasks, including triangulation, registration and scene reconstruction. While recalibration can be performed intraoperatively, this invariably results in a major disruption to workflow, and can be seen to represent a genuine barrier to the widespread adoption of image guidance technologies. The novel solution described herein constructs a model of the stereo endoscope across the continuum of focus settings, thereby reducing the number of degrees of freedom to one, such that a single view of reference geometry will determine the calibration uniquely. No special hardware or access to proprietary interfaces is required, and the method is ready for evaluation during human cases. A thorough quantitative analysis indicates that the resulting intrinsic and extrinsic parameters lead to calibrations as accurate as those derived from multiple pattern views.

  1. CALIBRATION OF THE INFRARED OPTOMETER

    Science.gov (United States)

    An infrared optometer for measuring the absolute status of accommodation is subject to a constant error not associated with chromatic aberration or...on optometer accuracy as long as the pupil does not vignette the optometer beam. A modification is described for calibrating the infrared optometer ...for an individual subject without using trial lenses or a subjective optometer . (Author)

  2. Measurement System and Calibration report

    DEFF Research Database (Denmark)

    Kock, Carsten Weber; Vesth, Allan

    This Measurement System & Calibration report is describing DTU’s measurement system installed at a specific wind turbine. A major part of the sensors has been installed by others (see [1]) the rest of the sensors have been installed by DTU. The results of the measurements, described in this report...

  3. Measurement System and Calibration report

    DEFF Research Database (Denmark)

    Vesth, Allan; Kock, Carsten Weber

    The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...

  4. Improved landmine detection through context-dependent score calibration

    Science.gov (United States)

    Smock, Brandon; Wilson, Joseph; Milner, Martin

    2016-05-01

    Algorithms developed for the detection of landmines are tasked with discriminating a wide variety of targets in a diverse array of environmental conditions. However, the potential performance of a detection algorithm may be underestimated by evaluating it in batch on a large, diverse dataset. This is because environmental, or in general, contextual, factors may contribute significant variance to the output of a detection algorithm across different contexts. One way to view this is as a problem of miscalibration: within each context, the output scores of a detection algorithm can be seen as miscalibrated relative to the scores produced in the other contexts. As a result of this miscalibration, the observed receiver operating characteristic (ROC) curve for a detector can have a sub-optimal area-under-the-curve (AUC). One solution, then, is to re-calibrate the detector within each context. In this work, we identify multiple sets of contexts in which different landmine detection algorithms exhibit significant output variance and, consequently, miscalibration. We then apply a monotonic calibration strategy that maximizes AUC and demonstrate the gain in observed performance that results when a landmine detection algorithm is properly calibrated within each context.

  5. Traditional and Model Based Assay of Irregular Geometry Items

    Energy Technology Data Exchange (ETDEWEB)

    MOORE, FRANK S.; SALAYMEH, SALEEM

    2005-06-15

    The Analytical Development Section (ADS) of SRNL was requested to perform a waste disposal assay of two heater boxes which had been used in the HB Line dissolvers. They had been sent to SRNL for study to make recommendations on how to prevent future failure of the units when they were replaced. The study having been completed, the units needed to be characterized prior to sending to Solid Waste for disposal. An assay station consisting of a turntable, HPGe detector, CANBERRA Inspector, transmission source and a portable computer was set up to do the required assays. The assays indicate the presence of U-235, Pu-239 and Cs-137. No measurable amounts of U-235 or Pu-239 were found. Therefore the Minimum Detectable Activities for U-235 and Pu-239 were calculated. For Heater Box 1, 0.23 grams of U-235 and 0.24 grams of Pu-239. For Heater Box 2, the results were 0.21 grams of U-235 and 0.21 grams of Pu-239. This paper describes and documents the assays employed to determine the amount of U, Pu and Cs contents of the heater boxes. The paper provides results of SNM assays using traditional calibration of the system and on one based on modeling. It also provides the scientific community with data that will assist the user in determining the method of choice for assaying items with irregular geometries.

  6. Radiation calibration for LWIR Hyperspectral Imager Spectrometer

    Science.gov (United States)

    Yang, Zhixiong; Yu, Chunchao; Zheng, Wei-jian; Lei, Zhenggang; Yan, Min; Yuan, Xiaochun; Zhang, Peizhong

    2014-11-01

    The radiometric calibration of LWIR Hyperspectral imager Spectrometer is presented. The lab has been developed to LWIR Interferometric Hyperspectral imager Spectrometer Prototype(CHIPED-I) to study Lab Radiation Calibration, Two-point linear calibration is carried out for the spectrometer by using blackbody respectively. Firstly, calibration measured relative intensity is converted to the absolute radiation lightness of the object. Then, radiation lightness of the object is is converted the brightness temperature spectrum by the method of brightness temperature. The result indicated †that this method of Radiation Calibration calibration was very good.

  7. Radio Interferometric Calibration Using a Riemannian Manifold

    CERN Document Server

    Yatawatta, Sarod

    2013-01-01

    In order to cope with the increased data volumes generated by modern radio interferometers such as LOFAR (Low Frequency Array) or SKA (Square Kilometre Array), fast and efficient calibration algorithms are essential. Traditional radio interferometric calibration is performed using nonlinear optimization techniques such as the Levenberg-Marquardt algorithm in Euclidean space. In this paper, we reformulate radio interferometric calibration as a nonlinear optimization problem on a Riemannian manifold. The reformulated calibration problem is solved using the Riemannian trust-region method. We show that calibration on a Riemannian manifold has faster convergence with reduced computational cost compared to conventional calibration in Euclidean space.

  8. Stable isotope dilution assays in mycotoxin analysis

    Energy Technology Data Exchange (ETDEWEB)

    Rychlik, Michael; Asam, Stefan [Universitaet Muenchen, Lehrstuhl fuer Lebensmittelchemie der Technischen, Garching (Germany)

    2008-01-15

    The principle and applications of stable isotope dilution assays (SIDAs) in mycotoxin analysis are critically reviewed. The general section includes historical aspects of SIDAs, the prerequisites and limitations of the use of stable isotopically labelled internal standards, and possible calibration procedures. In the application section actual SIDAs for the analysis of trichothecenes, zearalenone, fumonisins, patulin, and ochratoxin A are presented. The syntheses and availability of labelled mycotoxins for use as internal standards is reviewed and specific advances in food analysis and toxicology are demonstrated. The review indicates that LC-MS applications, in particular, require the use of stable isotopically labelled standards to compensate for losses during clean-up and for discrimination due to ion suppression. As the commercial availability of these compounds continues to increase, SIDAs can be expected to find expanding use in mycotoxin analysis. (orig.)

  9. Stable isotope dilution assays in mycotoxin analysis.

    Science.gov (United States)

    Rychlik, Michael; Asam, Stefan

    2008-01-01

    The principle and applications of stable isotope dilution assays (SIDAs) in mycotoxin analysis are critically reviewed. The general section includes historical aspects of SIDAs, the prerequisites and limitations of the use of stable isotopically labelled internal standards, and possible calibration procedures. In the application section actual SIDAs for the analysis of trichothecenes, zearalenone, fumonisins, patulin, and ochratoxin A are presented. The syntheses and availability of labelled mycotoxins for use as internal standards is reviewed and specific advances in food analysis and toxicology are demonstrated. The review indicates that LC-MS applications, in particular, require the use of stable isotopically labelled standards to compensate for losses during clean-up and for discrimination due to ion suppression. As the commercial availability of these compounds continues to increase, SIDAs can be expected to find expanding use in mycotoxin analysis.

  10. Radon assay for SNO+

    Energy Technology Data Exchange (ETDEWEB)

    Rumleskie, Janet [Laurentian University, Greater Sudbury, Ontario (Canada)

    2015-12-31

    The SNO+ experiment will study neutrinos while located 6,800 feet below the surface of the earth at SNOLAB. Though shielded from surface backgrounds, emanation of radon radioisotopes from the surrounding rock leads to back-grounds. The characteristic decay of radon and its daughters allows for an alpha detection technique to count the amount of Rn-222 atoms collected. Traps can collect Rn-222 from various positions and materials, including an assay skid that will collect Rn-222 from the organic liquid scintillator used to detect interactions within SNO+.

  11. FLUIDICS DEVICE FOR ASSAY

    DEFF Research Database (Denmark)

    2007-01-01

    The present invention relates to a device for use in performing assays on standard laboratory solid supports whereon chemical entities are attached. The invention furthermore relates to the use of such a device and a kit comprising such a device. The device according to the present invention is a......, when operatively connected, one or more chambers (21) comprising the chemical entities (41), the inlet(s) (5) and outlet(s) (6) and chambers (21) being in fluid connection. The device further comprise means for providing differing chemical conditions in each chamber (21)....

  12. Growth cone collapse assay.

    Science.gov (United States)

    Cook, Geoffrey M W; Jareonsettasin, Prem; Keynes, Roger J

    2014-01-01

    The growth cone collapse assay has proved invaluable in detecting and purifying axonal repellents. Glycoproteins/proteins present in detergent extracts of biological tissues are incorporated into liposomes, added to growth cones in culture and changes in morphology are then assessed. Alternatively purified or recombinant molecules in aqueous solution may be added directly to the cultures. In both cases after a defined period of time (up to 1 h), the cultures are fixed and then assessed by inverted phase contrast microscopy for the percentage of growth cones showing a collapsed profile with loss of flattened morphology, filopodia, and lamellipodia.

  13. Robust versatile tyrosine kinase assay for HTS in drug discovery

    Science.gov (United States)

    Deshpande, Sudhir S.; Mineyev, I.; Owicki, John C.

    1999-04-01

    A fluorescence polarization assay was developed as an alternative to the radiolabeled SPA assays currently used to monitor the activity of tyrosine kinases in drug discovery. The assay can be used with enzymes having substrate specificity similar to that of the insulin receptor, the EGF receptor and the Src kinase receptor enzymes. The assay is easy to configure in 96, 384 and 1536-well microplates in assay volumes ranging from (mu) L with minimal efforts. The reconstituted reagents are stable for up to 24 hr at ambient temperatures, thereby minimizing the need for replenishing the stock solutions during the course of a high-throughput screen. Because of the stability and equilibrium kinetics, the assay allows the user the luxury of scheduling the reading of plates any time up to 24 hr after the completion of the assay without substantial deterioration in the assay signal. The antibody and the tracer solutions can also be premixed and added as a preformed complex in a single step. The performance of the assay with the insulin receptor kinase is described. In addition, given the diversity of the substrates used in measuring the activity of different tyrosine kinases, LJL's on-going efforts to provide different antibodies of wide ranging specificity and sensitivity are described.

  14. RAS - Screens & Assays - Drug Discovery

    Science.gov (United States)

    The RAS Drug Discovery group aims to develop assays that will reveal aspects of RAS biology upon which cancer cells depend. Successful assay formats are made available for high-throughput screening programs to yield potentially effective drug compounds.

  15. Zoom lens calibration with zoom- and focus-related intrinsic parameters applied to bundle adjustment

    Science.gov (United States)

    Zheng, Shunyi; Wang, Zheng; Huang, Rongyong

    2015-04-01

    A zoom lens is more flexible for photogrammetric measurements under diverse environments than a fixed lens. However, challenges in calibration of zoom-lens cameras preclude the wide use of zoom lenses in the field of close-range photogrammetry. Thus, a novel zoom lens calibration method is proposed in this study. In this method, instead of conducting modeling after monofocal calibrations, we summarize the empirical zoom/focus models of intrinsic parameters first and then incorporate these parameters into traditional collinearity equations to construct the fundamental mathematical model, i.e., collinearity equations with zoom- and focus-related intrinsic parameters. Similar to monofocal calibration, images taken at several combinations of zoom and focus settings are processed in a single self-calibration bundle adjustment. In the self-calibration bundle adjustment, three types of unknowns, namely, exterior orientation parameters, unknown space point coordinates, and model coefficients of the intrinsic parameters, are solved simultaneously. Experiments on three different digital cameras with zoom lenses support the feasibility of the proposed method, and their relative accuracies range from 1:4000 to 1:15,100. Furthermore, the nominal focal length written in the exchangeable image file header is found to lack reliability in experiments. Thereafter, the joint influence of zoom lens instability and zoom recording errors is further analyzed quantitatively. The analysis result is consistent with the experimental result and explains the reason why zoom lens calibration can never have the same accuracy as monofocal self-calibration.

  16. SMAP RADAR Calibration and Validation

    Science.gov (United States)

    West, R. D.; Jaruwatanadilok, S.; Chaubel, M. J.; Spencer, M.; Chan, S. F.; Chen, C. W.; Fore, A.

    2015-12-01

    The Soil Moisture Active Passive (SMAP) mission launched on Jan 31, 2015. The mission employs L-band radar and radiometer measurements to estimate soil moisture with 4% volumetric accuracy at a resolution of 10 km, and freeze-thaw state at a resolution of 1-3 km. Immediately following launch, there was a three month instrument checkout period, followed by six months of level 1 (L1) calibration and validation. In this presentation, we will discuss the calibration and validation activities and results for the L1 radar data. Early SMAP radar data were used to check commanded timing parameters, and to work out issues in the low- and high-resolution radar processors. From April 3-13 the radar collected receive only mode data to conduct a survey of RFI sources. Analysis of the RFI environment led to a preferred operating frequency. The RFI survey data were also used to validate noise subtraction and scaling operations in the radar processors. Normal radar operations resumed on April 13. All radar data were examined closely for image quality and calibration issues which led to improvements in the radar data products for the beta release at the end of July. Radar data were used to determine and correct for small biases in the reported spacecraft attitude. Geo-location was validated against coastline positions and the known positions of corner reflectors. Residual errors at the time of the beta release are about 350 m. Intra-swath biases in the high-resolution backscatter images are reduced to less than 0.3 dB for all polarizations. Radiometric cross-calibration with Aquarius was performed using areas of the Amazon rain forest. Cross-calibration was also examined using ocean data from the low-resolution processor and comparing with the Aquarius wind model function. Using all a-priori calibration constants provided good results with co-polarized measurements matching to better than 1 dB, and cross-polarized measurements matching to about 1 dB in the beta release. During the

  17. Teaching Diversity

    Directory of Open Access Journals (Sweden)

    Kay Young McChesney

    2015-10-01

    Full Text Available This article is targeted to faculty teaching race and ethnicity, racism, diversity, and multicultural courses. Many students equate race with skin color. The premise of this article is that to teach students about the social construction of race, teachers must first know enough science to teach students that race is not biological. This article examines the biology of race by showing how advances in DNA sequencing led to genetics research that supports arguments that race is not biological. DNA comparisons show that all human populations living today are one species that came from Africa. The article explains the migration of humans out of Africa about 60,000 years ago and how they populated Australia, then Asia, Europe, and the Americas. The article shows how recent research maps the timing of the migration and admixture of specific population groups into Europe and India. The article shows how a mutation in one nucleotide can result in a trait like blue eyes, or Hemoglobin S (which confers resistance to malaria, which can be subject to evolution through natural selection. DNA comparisons show how natural selection shaped the genetics of human skin color to adapt to less UV light in the northern latitudes of Europe and Asia. The article shows that there is no relation between skin color or other “racial” characteristics and complex traits like intelligence. The science in this article will help teachers explain that as race is not biological, race is socially constructed and culturally enacted.

  18. NIR calibration of soluble stem carbohydrates for predicting drought tolerance in spring wheat

    Science.gov (United States)

    Soluble stem carbohydrates are a component of drought response in wheat (Triticum aestivum L.) and other grasses. Near-infrared spectroscopy (NIR) can rapidly assay for soluble carbohydrates indirectly, but this requires a statistical model for calibration. The objectives of this study were: (i) to ...

  19. New NIR Calibration Models Speed Biomass Composition and Reactivity Characterization

    Energy Technology Data Exchange (ETDEWEB)

    2015-09-01

    Obtaining accurate chemical composition and reactivity (measures of carbohydrate release and yield) information for biomass feedstocks in a timely manner is necessary for the commercialization of biofuels. This highlight describes NREL's work to use near-infrared (NIR) spectroscopy and partial least squares multivariate analysis to develop calibration models to predict the feedstock composition and the release and yield of soluble carbohydrates generated by a bench-scale dilute acid pretreatment and enzymatic hydrolysis assay. This highlight is being developed for the September 2015 Alliance S&T Board meeting.

  20. Calibration of the solar radio spectrometer

    Institute of Scientific and Technical Information of China (English)

    TAN ChengMing; YAN YiHua; TAN BaoLin; XU GuiRong

    2009-01-01

    This paper shows some improvements and new results of calibration of Chinese solar radio spectrom-eter by analyzing the daily calibration data recorded in the period of 1997-2007. First, the calibration coefficient is fitted for three bands (1.0-2.0 GHz, 2.6-3.8 GHz, 5.2-7.6 GHz) of the spectrometer by using the moving-average method confined by the property of the daily calibration data. By this calibration coefficient, the standard deviation of the calibration result was less than 10 sfu for 95% frequencies of 2.6-3.8 GHz band in 2003. This result is better than that calibrated with the constant coefficient. Second, the calibration coefficient is found in good correlation with local air temperature for most frequencies of 2.6-3.8 GHz band. Moreover, these results are helpful in the research of the quiet solar radio emission.

  1. Crop physiology calibration in the CLM

    Directory of Open Access Journals (Sweden)

    I. Bilionis

    2015-04-01

    scalable and adaptive scheme based on sequential Monte Carlo (SMC. The model showed significant improvement of crop productivity with the new calibrated parameters. We demonstrate that the calibrated parameters are applicable across alternative years and different sites.

  2. Calibration of the solar radio spectrometer

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This paper shows some improvements and new results of calibration of Chinese solar radio spectrometer by analyzing the daily calibration data recorded in the period of 1997-2007. First, the calibration coefficient is fitted for three bands (1.0-2.0 GHz, 2.6-3.8 GHz, 5.2-7.6 GHz) of the spectrometer by using the moving-average method confined by the property of the daily calibration data. By this calibration coefficient, the standard deviation of the calibration result was less than 10 sfu for 95% frequencies of 2.6-3.8 GHz band in 2003. This result is better than that calibrated with the constant coefficient. Second, the calibration coefficient is found in good correlation with local air temperature for most frequencies of 2.6-3.8 GHz band. Moreover, these results are helpful in the research of the quiet solar radio emission.

  3. Calibration and Validation of Measurement System

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Riemann, Sven; Knapp, Wilfried

    The report deals with the calibration of the measuring equipment on board the Wave Dragon, Nissum Bredning prototype.......The report deals with the calibration of the measuring equipment on board the Wave Dragon, Nissum Bredning prototype....

  4. Optimal Reliability-Based Code Calibration

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Kroon, I. B.; Faber, M. H.

    1994-01-01

    Calibration of partial safety factors is considered in general, including classes of structures where no code exists beforehand. The partial safety factors are determined such that the difference between the reliability for the different structures in the class considered and a target reliability...... level is minimized. Code calibration on a decision theoretical basis is also considered and it is shown how target reliability indices can be calibrated. Results from code calibration for rubble mound breakwater designs are shown....

  5. Calibration of a Parallel Kinematic Machine Tool

    Institute of Scientific and Technical Information of China (English)

    HE Xiao-mei; DING Hong-sheng; FU Tie; XIE Dian-huang; XU Jin-zhong; LI Hua-feng; LIU Hui-lin

    2006-01-01

    A calibration method is presented to enhance the static accuracy of a parallel kinematic machine tool by using a coordinate measuring machine and a laser tracker. According to the established calibration model and the calibration experiment, the factual 42 kinematic parameters of BKX-I parallel kinematic machine tool are obtained. By circular tests the comparison is made between the calibrated and the uncalibrated parameters and shows that there is 80% improvement in accuracy of this machine tool.

  6. A Careful Consideration of the Calibration Concept

    Science.gov (United States)

    Phillips, S. D.; Estler, W. T.; Doiron, T.; Eberhardt, K. R.; Levenson, M. S.

    2001-01-01

    This paper presents a detailed discussion of the technical aspects of the calibration process with emphasis on the definition of the measurand, the conditions under which the calibration results are valid, and the subsequent use of the calibration results in measurement uncertainty statements. The concepts of measurement uncertainty, error, systematic error, and reproducibility are also addressed as they pertain to the calibration process. PMID:27500027

  7. Calibrating thermal behavior of electronics

    Energy Technology Data Exchange (ETDEWEB)

    Chainer, Timothy J.; Parida, Pritish R.; Schultz, Mark D.

    2017-01-03

    A method includes determining a relationship between indirect thermal data for a processor and a measured temperature associated with the processor, during a calibration process, obtaining the indirect thermal data for the processor during actual operation of the processor, and determining an actual significant temperature associated with the processor during the actual operation using the indirect thermal data for the processor during actual operation of the processor and the relationship.

  8. Nonlinear Observers for Gyro Calibration

    Science.gov (United States)

    Thienel, Julie; Sanner, Robert M.

    2003-01-01

    Nonlinear observers for gyro calibration are presented. The first observer estimates a constant gyro bias. The second observer estimates scale factor errors. The third observer estimates the gyro alignment for three orthogonal gyros. The convergence properties of all three observers are discussed. Additionally, all three observers are coupled with a nonlinear control algorithm. The stability of each of the resulting closed loop systems is analyzed. Simulated test results are presented for each system.

  9. Calibrating thermal behavior of electronics

    Science.gov (United States)

    Chainer, Timothy J.; Parida, Pritish R.; Schultz, Mark D.

    2016-05-31

    A method includes determining a relationship between indirect thermal data for a processor and a measured temperature associated with the processor, during a calibration process, obtaining the indirect thermal data for the processor during actual operation of the processor, and determining an actual significant temperature associated with the processor during the actual operation using the indirect thermal data for the processor during actual operation of the processor and the relationship.

  10. Model Calibration in Watershed Hydrology

    Science.gov (United States)

    Yilmaz, Koray K.; Vrugt, Jasper A.; Gupta, Hoshin V.; Sorooshian, Soroosh

    2009-01-01

    Hydrologic models use relatively simple mathematical equations to conceptualize and aggregate the complex, spatially distributed, and highly interrelated water, energy, and vegetation processes in a watershed. A consequence of process aggregation is that the model parameters often do not represent directly measurable entities and must, therefore, be estimated using measurements of the system inputs and outputs. During this process, known as model calibration, the parameters are adjusted so that the behavior of the model approximates, as closely and consistently as possible, the observed response of the hydrologic system over some historical period of time. This Chapter reviews the current state-of-the-art of model calibration in watershed hydrology with special emphasis on our own contributions in the last few decades. We discuss the historical background that has led to current perspectives, and review different approaches for manual and automatic single- and multi-objective parameter estimation. In particular, we highlight the recent developments in the calibration of distributed hydrologic models using parameter dimensionality reduction sampling, parameter regularization and parallel computing.

  11. Unassisted 3D camera calibration

    Science.gov (United States)

    Atanassov, Kalin; Ramachandra, Vikas; Nash, James; Goma, Sergio R.

    2012-03-01

    With the rapid growth of 3D technology, 3D image capture has become a critical part of the 3D feature set on mobile phones. 3D image quality is affected by the scene geometry as well as on-the-device processing. An automatic 3D system usually assumes known camera poses accomplished by factory calibration using a special chart. In real life settings, pose parameters estimated by factory calibration can be negatively impacted by movements of the lens barrel due to shaking, focusing, or camera drop. If any of these factors displaces the optical axes of either or both cameras, vertical disparity might exceed the maximum tolerable margin and the 3D user may experience eye strain or headaches. To make 3D capture more practical, one needs to consider unassisted (on arbitrary scenes) calibration. In this paper, we propose an algorithm that relies on detection and matching of keypoints between left and right images. Frames containing erroneous matches, along with frames with insufficiently rich keypoint constellations, are detected and discarded. Roll, pitch yaw , and scale differences between left and right frames are then estimated. The algorithm performance is evaluated in terms of the remaining vertical disparity as compared to the maximum tolerable vertical disparity.

  12. Variability among polysulphone calibration curves

    Energy Technology Data Exchange (ETDEWEB)

    Casale, G R [University of Rome ' La Sapienza' , Physics Department, P.le A. Moro 2, I-00185, Rome (Italy); Borra, M [ISPESL - Istituto Superiore per la Prevenzione E la Sicurezza del Lavoro, Occupational Hygiene Department, Via Fontana Candida 1, I-0040 Monteporzio Catone (RM) (Italy); Colosimo, A [University of Rome ' La Sapienza' , Department of Human Physiology and Pharmacology, P.le A. Moro 2, I-00185, Rome (Italy); Colucci, M [ISPESL - Istituto Superiore per la Prevenzione E la Sicurezza del Lavoro, Occupational Hygiene Department, Via Fontana Candida 1, I-0040 Monteporzio Catone (RM) (Italy); Militello, A [ISPESL - Istituto Superiore per la Prevenzione E la Sicurezza del Lavoro, Occupational Hygiene Department, Via Fontana Candida 1, I-0040 Monteporzio Catone (RM) (Italy); Siani, A M [University of Rome ' La Sapienza' , Physics Department, P.le A. Moro 2, I-00185, Rome (Italy); Sisto, R [ISPESL - Istituto Superiore per la Prevenzione E la Sicurezza del Lavoro, Occupational Hygiene Department, Via Fontana Candida 1, I-0040 Monteporzio Catone (RM) (Italy)

    2006-09-07

    Within an epidemiological study regarding the correlation between skin pathologies and personal ultraviolet (UV) exposure due to solar radiation, 14 field campaigns using polysulphone (PS) dosemeters were carried out at three different Italian sites (urban, semi-rural and rural) in every season of the year. A polysulphone calibration curve for each field experiment was obtained by measuring the ambient UV dose under almost clear sky conditions and the corresponding change in the PS film absorbance, prior and post exposure. Ambient UV doses were measured by well-calibrated broad-band radiometers and by electronic dosemeters. The dose-response relation was represented by the typical best fit to a third-degree polynomial and it was parameterized by a coefficient multiplying a cubic polynomial function. It was observed that the fit curves differed from each other in the coefficient only. It was assessed that the multiplying coefficient was affected by the solar UV spectrum at the Earth's surface whilst the polynomial factor depended on the photoinduced reaction of the polysulphone film. The mismatch between the polysulphone spectral curve and the CIE erythemal action spectrum was responsible for the variability among polysulphone calibration curves. The variability of the coefficient was related to the total ozone amount and the solar zenith angle. A mathematical explanation of such a parameterization was also discussed.

  13. PACS photometer calibration block analysis

    CERN Document Server

    Moór, A; Kiss, Cs; Balog, Z; Billot, N; Marton, G

    2013-01-01

    The absolute stability of the PACS bolometer response over the entire mission lifetime without applying any corrections is about 0.5% (standard deviation) or about 8% peak-to-peak. This fantastic stability allows us to calibrate all scientific measurements by a fixed and time-independent response file, without using any information from the PACS internal calibration sources. However, the analysis of calibration block observations revealed clear correlations of the internal source signals with the evaporator temperature and a signal drift during the first half hour after the cooler recycling. These effects are small, but can be seen in repeated measurements of standard stars. From our analysis we established corrections for both effects which push the stability of the PACS bolometer response to about 0.2% (stdev) or 2% in the blue, 3% in the green and 5% in the red channel (peak-to-peak). After both corrections we still see a correlation of the signals with PACS FPU temperatures, possibly caused by parasitic h...

  14. Bacterial assays for recombinagens.

    Science.gov (United States)

    Hoffmann, G R

    1992-12-01

    Two principal strategies have been used for studying recombinagenic effects of chemicals and radiation in bacteria: (1) measurement of homologous recombination involving defined alleles in a partially diploid strain, and (2) measurement of the formation and loss of genetic duplications in the bacterial chromosome. In the former category, most methods involve one allele in the bacterial chromosome and another in a plasmid, but it is also possible to detect recombination between two chromosomal alleles or between two extrachromosomal alleles. This review summarizes methods that use each of these approaches for detecting recombination and tabulates data on agents that have been found to be recombinagenic in bacteria. The assays are discussed with respect to their effectiveness in testing for recombinagens and their potential for elucidating mechanisms underlying recombinagenic effects.

  15. Net analyte signal calculation for multivariate calibration

    NARCIS (Netherlands)

    Ferre, J.; Faber, N.M.

    2003-01-01

    A unifying framework for calibration and prediction in multivariate calibration is shown based on the concept of the net analyte signal (NAS). From this perspective, the calibration step can be regarded as the calculation of a net sensitivity vector, whose length is the amount of net signal when the

  16. Optimal, Reliability-Based Code Calibration

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    2002-01-01

    Reliability based code calibration is considered in this paper. It is described how the results of FORM based reliability analysis may be related to the partial safety factors and characteristic values. The code calibration problem is presented in a decision theoretical form and it is discussed how...... of reliability based code calibration of LRFD based design codes....

  17. Code Calibration as a Decision Problem

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Kroon, I. B.; Faber, M. H.

    1993-01-01

    Calibration of partial coefficients for a class of structures where no code exists is considered. The partial coefficients are determined such that the difference between the reliability for the different structures in the class considered and a target reliability level is minimized. Code...... calibration on a decision theoretical basis is discussed. Results from code calibration for rubble mound breakwater designs are shown....

  18. Systems and methods of eye tracking calibration

    DEFF Research Database (Denmark)

    2014-01-01

    Methods and systems to facilitate eye tracking control calibration are provided. One or more objects are displayed on a display of a device, where the one or more objects are associated with a function unrelated to a calculation of one or more calibration parameters. The one or more calibration...

  19. 14 CFR 33.45 - Calibration tests.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Calibration tests. 33.45 Section 33.45... STANDARDS: AIRCRAFT ENGINES Block Tests; Reciprocating Aircraft Engines § 33.45 Calibration tests. (a) Each engine must be subjected to the calibration tests necessary to establish its power characteristics...

  20. 14 CFR 33.85 - Calibration tests.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Calibration tests. 33.85 Section 33.85... STANDARDS: AIRCRAFT ENGINES Block Tests; Turbine Aircraft Engines § 33.85 Calibration tests. (a) Each engine must be subjected to those calibration tests necessary to establish its power characteristics and...

  1. DOE assay methods used for characterization of contact-handled transuranic waste

    Energy Technology Data Exchange (ETDEWEB)

    Schultz, F.J. (Oak Ridge National Lab., TN (United States)); Caldwell, J.T. (Pajarito Scientific Corp., Los Alamos, NM (United States))

    1991-08-01

    US Department of Energy methods used for characterization of contact-handled transuranic (CH-TRU) waste prior to shipment to the Waste Isolation Pilot Plant (WIPP) are described and listed by contractor site. The methods described are part of the certification process. All CH-TRU waste must be assayed for determination of fissile material content and decay heat values prior to shipment and prior to storage on-site. Both nondestructive assay (NDA) and destructive assay methods are discussed, and new NDA developments such as passive-action neutron (PAN) crate counter improvements and neutron imaging are detailed. Specifically addressed are assay method physics; applicability to CH-TRU wastes; calibration standards and implementation; operator training requirements and practices; assay procedures; assay precision, bias, and limit of detection; and assay limitation. While PAN is a new technique and does not yet have established American Society for Testing and Materials. American National Standards Institute, or Nuclear Regulatory Commission guidelines or methods describing proper calibration procedures, equipment setup, etc., comparisons of PAN data with the more established assay methods (e.g., segmented gamma scanning) have demonstrated its reliability and accuracy. Assay methods employed by DOE have been shown to reliable and accurate in determining fissile, radionuclide, alpha-curie content, and decay heat values of CH-TRU wastes. These parameters are therefore used to characterize packaged waste for use in certification programs such as that used in shipment of CH-TRU waste to the WIPP. 36 refs., 10 figs., 7 tabs.

  2. 42 CFR 493.1255 - Standard: Calibration and calibration verification procedures.

    Science.gov (United States)

    2010-10-01

    ..., if possible, traceable to a reference method or reference material of known value; and (ii) Including... 42 Public Health 5 2010-10-01 2010-10-01 false Standard: Calibration and calibration verification... for Nonwaived Testing Analytic Systems § 493.1255 Standard: Calibration and calibration...

  3. Engineering luciferase enzymes and substrates for novel assay capabilities

    Science.gov (United States)

    Wood, Keith V.

    2004-06-01

    In the development of HTS as a central paradigm of drug discovery, fluorescent reporter molecules have generally been adopted as the favored signal transducer. Nevertheless, luminescence has maintained a prominent position among certain methodologies, most notably genetic reporters. Recently, there has been growing partiality for luminescent assays across a broader range of applications due to their sensitivity, extensive linearity, and robustness to library compounds and complex biological samples. This trend has been fostered by development several new assay designs for diverse targets such as kinases, cytochrome p450's, proteases, apoptosis, and cytotoxicity. This review addresses recent progress made in the use of bioluminescent assays for drug discovery, highlighting new detection capabilities brought about by engineering luciferase enzymes and substrates. In reporter gene applications, modified luciferases have provided greatly improved expression efficiency in mammalian cells, improved responsiveness to changes of transcriptional rate, and increased the magnitude of the reporter response. Highly stabilized luciferase mutants have enabled new assays strategies for high-throughput screening based on detection of ATP and luciferin. Assays based on ATP support rapid analysis of cell metabolism and enzymatic processes coupled to ATP hydrolysis. Although luciferin is found natively only in luminous beetles, coupled assays have been designed using modified forms of luciferin requiring the action of second enzyme to yield luminescence. Due to the very low inherent background and protection of the photon-emitter afforded by the enzyme, bioluminescent assays often outperform the analogous fluorescent assays for analyses performed in multiwell plates.

  4. Spectral calibration for convex grating imaging spectrometer

    Science.gov (United States)

    Zhou, Jiankang; Chen, Xinhua; Ji, Yiqun; Chen, Yuheng; Shen, Weimin

    2013-12-01

    Spectral calibration of imaging spectrometer plays an important role for acquiring target accurate spectrum. There are two spectral calibration types in essence, the wavelength scanning and characteristic line sampling. Only the calibrated pixel is used for the wavelength scanning methods and he spectral response function (SRF) is constructed by the calibrated pixel itself. The different wavelength can be generated by the monochromator. The SRF is constructed by adjacent pixels of the calibrated one for the characteristic line sampling methods. And the pixels are illuminated by the narrow spectrum line and the center wavelength of the spectral line is exactly known. The calibration result comes from scanning method is precise, but it takes much time and data to deal with. The wavelength scanning method cannot be used in field or space environment. The characteristic line sampling method is simple, but the calibration precision is not easy to confirm. The standard spectroscopic lamp is used to calibrate our manufactured convex grating imaging spectrometer which has Offner concentric structure and can supply high resolution and uniform spectral signal. Gaussian fitting algorithm is used to determine the center position and the Full-Width-Half-Maximum(FWHM)of the characteristic spectrum line. The central wavelengths and FWHMs of spectral pixels are calibrated by cubic polynomial fitting. By setting a fitting error thresh hold and abandoning the maximum deviation point, an optimization calculation is achieved. The integrated calibration experiment equipment for spectral calibration is developed to enhance calibration efficiency. The spectral calibration result comes from spectral lamp method are verified by monochromator wavelength scanning calibration technique. The result shows that spectral calibration uncertainty of FWHM and center wavelength are both less than 0.08nm, or 5.2% of spectral FWHM.

  5. Gemini Planet Imager Observational Calibrations II: Detector Performance and Calibration

    CERN Document Server

    Ingraham, Patrick; Sadakuni, Naru; Ruffio, Jean-Baptiste; Maire, Jerome; Chilcote, Jeff; Larkin, James; Marchis, Franck; Galicher, Raphael; Weiss, Jason

    2014-01-01

    The Gemini Planet Imager is a newly commissioned facility instrument designed to measure the near-infrared spectra of young extrasolar planets in the solar neighborhood and obtain imaging polarimetry of circumstellar disks. GPI's science instrument is an integral field spectrograph that utilizes a HAWAII-2RG detector with a SIDECAR ASIC readout system. This paper describes the detector characterization and calibrations performed by the GPI Data Reduction Pipeline to compensate for effects including bad/hot/cold pixels, persistence, non-linearity, vibration induced microphonics and correlated read noise.

  6. Development of a TaqMan assay for the six major genotypes of hepatitis C virus: Comparison with commercial assays

    DEFF Research Database (Denmark)

    Engle, Ronald E; Russell, Rodney S; Purcell, Robert H;

    2008-01-01

    A quantitative real-time PCR assay was developed that detects genomic RNA from reference strains representing the six major genotypes of hepatitis C virus (HCV) with equal sensitivity and accurately measured HCV RNA in JFH1 HCV-infected Huh7.5 cells. The method is indirectly calibrated to the first...... (Versant HCV RNA 3.0 b-DNA and Amplicor HCV Monitor), that also employ the WHO standard, allowed validation of the TaqMan assay against all major HCV genotypes. Both commercial methods detected HCV RNA over a wide dynamic range, but showed a consistent difference of about 0.3 log10 when evaluating samples...... of different HCV genotypes. The genome titers obtained with the three methods correlated with the infectivity titers previously determined for the HCV reference strains. TaqMan assays have become an essential tool to follow viral load in clinical samples and cell culture-based experiments and this technology...

  7. Calibrating a high-Esolution wavefront corrector with a static focal-Plane camera

    NARCIS (Netherlands)

    Korkiakoski, V.; Doelman, N.J.; Codona, J.; Kenworthy, M.; Otten, G.; Keller, C.U.

    2013-01-01

    We present a method to calibrate a high-resolution wavefront (WF)-correcting device with a single, static camera, located in the focal-plane; no moving of any component is needed. The method is based on a localized diversity and differential optical transfer functions to compute both the phase and a

  8. Photometric Calibrations for the SIRTF Infrared Spectrograph

    CERN Document Server

    Morris, P W; Herter, T L; Armus, L; Houck, J; Sloan, G

    2002-01-01

    The SIRTF InfraRed Spectrograph (IRS) is faced with many of the same calibration challenges that were experienced in the ISO SWS calibration program, owing to similar wavelength coverage and overlapping spectral resolutions of the two instruments. Although the IRS is up to ~300 times more sensitive and without moving parts, imposing unique calibration challenges on their own, an overlap in photometric sensitivities of the high-resolution modules with the SWS grating sections allows lessons, resources, and certain techniques from the SWS calibration programs to be exploited. We explain where these apply in an overview of the IRS photometric calibration planning.

  9. Hyperpolarized NMR Probes for Biological Assays

    Directory of Open Access Journals (Sweden)

    Sebastian Meier

    2014-01-01

    Full Text Available During the last decade, the development of nuclear spin polarization enhanced (hyperpolarized molecular probes has opened up new opportunities for studying the inner workings of living cells in real time. The hyperpolarized probes are produced ex situ, introduced into biological systems and detected with high sensitivity and contrast against background signals using high resolution NMR spectroscopy. A variety of natural, derivatized and designed hyperpolarized probes has emerged for diverse biological studies including assays of intracellular reaction progression, pathway kinetics, probe uptake and export, pH, redox state, reactive oxygen species, ion concentrations, drug efficacy or oncogenic signaling. These probes are readily used directly under natural conditions in biofluids and are often directly developed and optimized for cellular assays, thus leaving little doubt about their specificity and utility under biologically relevant conditions. Hyperpolarized molecular probes for biological NMR spectroscopy enable the unbiased detection of complex processes by virtue of the high spectral resolution, structural specificity and quantifiability of NMR signals. Here, we provide a survey of strategies used for the selection, design and use of hyperpolarized NMR probes in biological assays, and describe current limitations and developments.

  10. Muon Energy Calibration of the MINOS Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Miyagawa, Paul S.

    2004-09-01

    MINOS is a long-baseline neutrino oscillation experiment designed to search for conclusive evidence of neutrino oscillations and to measure the oscillation parameters precisely. MINOS comprises two iron tracking calorimeters located at Fermilab and Soudan. The Calibration Detector at CERN is a third MINOS detector used as part of the detector response calibration programme. A correct energy calibration between these detectors is crucial for the accurate measurement of oscillation parameters. This thesis presents a calibration developed to produce a uniform response within a detector using cosmic muons. Reconstruction of tracks in cosmic ray data is discussed. This data is utilized to calculate calibration constants for each readout channel of the Calibration Detector. These constants have an average statistical error of 1.8%. The consistency of the constants is demonstrated both within a single run and between runs separated by a few days. Results are presented from applying the calibration to test beam particles measured by the Calibration Detector. The responses are calibrated to within 1.8% systematic error. The potential impact of the calibration on the measurement of oscillation parameters by MINOS is also investigated. Applying the calibration reduces the errors in the measured parameters by {approx} 10%, which is equivalent to increasing the amount of data by 20%.

  11. Muon Energy Calibration of the MINOS Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Miyagawa, Paul S. [Somerville College, Oxford (United Kingdom)

    2004-01-01

    MINOS is a long-baseline neutrino oscillation experiment designed to search for conclusive evidence of neutrino oscillations and to measure the oscillation parameters precisely. MINOS comprises two iron tracking calorimeters located at Fermilab and Soudan. The Calibration Detector at CERN is a third MINOS detector used as part of the detector response calibration programme. A correct energy calibration between these detectors is crucial for the accurate measurement of oscillation parameters. This thesis presents a calibration developed to produce a uniform response within a detector using cosmic muons. Reconstruction of tracks in cosmic ray data is discussed. This data is utilized to calculate calibration constants for each readout channel of the Calibration Detector. These constants have an average statistical error of 1.8%. The consistency of the constants is demonstrated both within a single run and between runs separated by a few days. Results are presented from applying the calibration to test beam particles measured by the Calibration Detector. The responses are calibrated to within 1.8% systematic error. The potential impact of the calibration on the measurement of oscillation parameters by MINOS is also investigated. Applying the calibration reduces the errors in the measured parameters by ~ 10%, which is equivalent to increasing the amount of data by 20%.

  12. "Calibration-on-the-spot": How to calibrate an EMCCD camera from its images.

    Science.gov (United States)

    Mortensen, Kim I; Flyvbjerg, Henrik

    2016-07-06

    In order to count photons with a camera, the camera must be calibrated. Photon counting is necessary, e.g., to determine the precision of localization-based super-resolution microscopy. Here we present a protocol that calibrates an EMCCD camera from information contained in isolated, diffraction-limited spots in any image taken by the camera, thus making dedicated calibration procedures redundant by enabling calibration post festum, from images filed without calibration information.

  13. Calibration-on-the-spot”: How to calibrate an EMCCD camera from its images

    DEFF Research Database (Denmark)

    Mortensen, Kim; Flyvbjerg, Henrik

    2016-01-01

    In order to count photons with a camera, the camera must be calibrated. Photon counting is necessary, e.g., to determine the precision of localization-based super-resolution microscopy. Here we present a protocol that calibrates an EMCCD camera from information contained in isolated, diffraction......-limited spots in any image taken by the camera, thus making dedicated calibration procedures redundant by enabling calibration post festum, from images filed without calibration information....

  14. Verification of L-band SAR calibration

    Science.gov (United States)

    Larson, R. W.; Jackson, P. L.; Kasischke, E.

    1985-01-01

    Absolute calibration of a digital L-band SAR system to an accuracy of better than 3 dB has been verified. This was accomplished with a calibration signal generator that produces the phase history of a point target. This signal relates calibration values to various SAR data sets. Values of radar cross-section (RCS) of reference reflectors were obtained using a derived calibration relationship for the L-band channel on the ERIM/CCRS X-C-L SAR system. Calibrated RCS values were compared to known RCS values of each reference reflector for verification and to obtain an error estimate. The calibration was based on the radar response to 21 calibrated reference reflectors.

  15. Calibration of the Cherenkov Telescope Array

    CERN Document Server

    Gaug, Markus; Berge, David; Reyes, Raquel de los; Doro, Michele; Foerster, Andreas; Maccarone, Maria Concetta; Parsons, Dan; van Eldik, Christopher

    2015-01-01

    The construction of the Cherenkov Telescope Array is expected to start soon. We will present the baseline methods and their extensions currently foreseen to calibrate the observatory. These are bound to achieve the strong requirements on allowed systematic uncertainties for the reconstructed gamma-ray energy and flux scales, as well as on the pointing resolution, and on the overall duty cycle of the observatory. Onsite calibration activities are designed to include a robust and efficient calibration of the telescope cameras, and various methods and instruments to achieve calibration of the overall optical throughput of each telescope, leading to both inter-telescope calibration and an absolute calibration of the entire observatory. One important aspect of the onsite calibration is a correct understanding of the atmosphere above the telescopes, which constitutes the calorimeter of this detection technique. It is planned to be constantly monitored with state-of-the-art instruments to obtain a full molecular and...

  16. Radio Interferometric Calibration Using The SAGE Algorithm

    CERN Document Server

    Kazemi, S; Zaroubi, S; de Bruyn, A G; Koopmans, L V E; Noordam, J

    2010-01-01

    The aim of the new generation of radio synthesis arrays such as LOFAR and SKA is to achieve much higher sensitivity, resolution and frequency coverage than what is available now. To accomplish this goal, the accuracy of the calibration techniques used is of considerable importance. Moreover, since these telescopes produce huge amounts of data, speed of convergence of calibration is a major bottleneck. The errors in calibration are due to system noise (sky and instrumental) as well as the estimation errors introduced by the calibration technique itself, which we call "solver noise". We define solver noise as the "distance" between the optimal solution, the true value of the unknowns corrupted by the system noise, and the solution obtained by calibration. We present the Space Alternating Generalized Expectation Maximization (SAGE) calibration technique, which is a modification of the Expectation Maximization algorithm, and compare its performance with the traditional Least Squares calibration based on the level...

  17. Herbicide resistance screening assay.

    Science.gov (United States)

    Peterson, Joan M

    2009-01-01

    Herbicide resistance screening is a method that can be used not only to determine presence of the enzyme, phosphinothricin acetyltransferase, encoded by either the Bar or the Pat gene in transgenic maize, but also to assess the inheritance ratio of those genes in a segregating population. Herbicide screening can also be used to study linkage of a transgene of interest that was cotransformed with the herbicide resistance marker gene. By combining the herbicide screen assay with a PCR-based screen of leaf tissue DNA for the presence of both the Bar or the Pat gene marker and a cotransformed transgene of interest from the same seedling tissue and maintaining that seedling identity, the researcher can identify linkage or the possible breakdown in linkage of the marker gene and the transgene of interest. Further, the occurrence of "DNA silencing" can be evaluated if an individual seedling that was susceptible to the applied herbicide nonetheless gave PCR data that indicated presence of the gene responsible for herbicide resistance. Similarly, "DNA silencing" of the gene of interest may be investigated if the seeds can be screened and scored for that phenotypic trait in a nondestructive manner prior to planting.

  18. Training In Diversity Management

    Directory of Open Access Journals (Sweden)

    Sonja Treven

    2011-07-01

    Full Text Available The labor force all around the world is becoming increasingly diverse. Thus, organizations that can manage employee diversity effectively gain a competitive advantage. In such organizations diversity training is a necessity. Diversity training helps managers understand and value individual differences and develop strong diagnostic skills. The paper explores various approaches to training, like awareness-based and skill-based diversity training. A special attention to potential problems that may occur in the process of diversity training is given.

  19. Calibration of TOB+ Thermometer's Cards

    CERN Document Server

    Banitt, Daniel

    2014-01-01

    Motivation - Under the new upgrade of the CMS detector the working temperature of the trackers had been reduced to -27 Celsius degrees. Though the thermal sensors themselves (Murata and Fenwal thermistors) are effective at these temperatures, the max1542 PLC (programmable logic controller) cards, interpreting the resistance of the thermal sensors into DC counts usable by the DCS (detector control system), are not designed for these temperatures in which the counts exceed their saturation and therefor had to be replaced. In my project I was in charge of handling the emplacement and calibration of the new PLC cards to the TOB (tracker outer barrel) control system.

  20. AFFTC Standard Airspeed Calibration Procedures

    Science.gov (United States)

    1981-06-01

    25x0UIXQXQ Results of groundLpeed course calibration are normally pre- sented in the following plots: 1. .AvP vs Vi Ŗ. All vs V ic 3. AMPC vs Mic .4...8217Average AfPeavgpo, tion correction AM /AH 10-5 per and figure V 9 PC PC feet . fu V AYpc" x q3 @ , Average position avg corred ion (AM @ AMPC /AVPC...instrument error 0 M ic From and 0), Mach number p Chart 8.5 in reference’l (AFTR 6273) (DO AMPPacer poqition error calibra- Pc tion at9 S( AMpc /’,HpC)p

  1. Diversity: A Philosophical Perspective

    Directory of Open Access Journals (Sweden)

    Sahotra Sarkar

    2010-01-01

    Full Text Available In recent years, diversity, whether it be ecological, biological, cultural, or linguistic diversity, has emerged as a major cultural value. This paper analyzes whether a single concept of diversity can underwrite discussions of diversity in different disciplines. More importantly, it analyzes the normative justification for the endorsement of diversity as a goal in all contexts. It concludes that no more than a relatively trivial concept of diversity as richness is common to all contexts. Moreover, there is no universal justification for the endorsement of diversity. Arguments to justify the protection of diversity must be tailored to individual contexts.

  2. An accurate system for onsite calibration of electronic transformers with digital output

    Science.gov (United States)

    Zhi, Zhang; Li, Hong-Bin

    2012-06-01

    Calibration systems with digital output are used to replace conventional calibration systems because of principle diversity and characteristics of digital output of electronic transformers. But precision and unpredictable stability limit their onsite application even development. So fully considering the factors influencing accuracy of calibration system and employing simple but reliable structure, an all-digital calibration system with digital output is proposed in this paper. In complicated calibration environments, precision and dynamic range are guaranteed by A/D converter with 24-bit resolution, synchronization error limit is nanosecond by using the novelty synchronization method. In addition, an error correction algorithm based on the differential method by using two-order Hanning convolution window has good inhibition of frequency fluctuation and inter-harmonics interference. To verify the effectiveness, error calibration was carried out in the State Grid Electric Power Research Institute of China and results show that the proposed system can reach the precision class up to 0.05. Actual onsite calibration shows that the system has high accuracy, and is easy to operate with satisfactory stability.

  3. Pulse-based internal calibration of polarimetric SAR

    DEFF Research Database (Denmark)

    Dall, Jørgen; Skou, Niels; Christensen, Erik Lintz

    1994-01-01

    Internal calibration greatly diminishes the dependence on calibration target deployment compared to external calibration. Therefore the Electromagnetics Institute (EMI) at the Technical University of Denmark (TUD) has equipped its polarimetric SAR, EMISAR, with several calibration loops and devel......Internal calibration greatly diminishes the dependence on calibration target deployment compared to external calibration. Therefore the Electromagnetics Institute (EMI) at the Technical University of Denmark (TUD) has equipped its polarimetric SAR, EMISAR, with several calibration loops...

  4. CALIBRATION OF SEISMIC ATTRIBUTES FOR RESERVOIR CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Wayne D. Pennington

    2001-04-01

    The project, ''Calibration of Seismic Attributes for Reservoir Calibration,'' is on schedule and making unplanned discoveries in addition to those intended when the project commenced. The discoveries, planned and unplanned, can be grouped into four classes: pitfalls to avoid in interpretation of seismic attributes; suggested workflows to follow in working with seismic attributes; new methods of calculating certain new attributes which we feel to be useful; and new theoretical approaches to certain petrophysical properties. We are using data from Wyoming, North Texas, South Texas, and the Gulf of Mexico offshore of Louisiana. These environments provide a diverse array of physical conditions and rock types, and a variety of interpretation methods to be applied to them. The Wyoming field is a very difficult one, including alternating layers of thin beds of coals, shales, and hard sandstones, and there may be an observable effect due to hydrocarbon production; we are using this field as the ''test'' of those techniques and methods we have developed or that we prefer based on our work on the other fields. Work on this field is still underway, although progressing nicely. The work on the public domain data sets in Texas, Boonsville and Stratton, is complete except for some minor additional processing steps, and final write-ups are underway. The work on the Gulf of Mexico field has been completed to the extent originally planned, but it has led us to such important new observations and discoveries that we have expanded our original scope to include time-lapse studies and petrophysical aspects of pressure changes; work on this expanded scope is continuing. Presentations have been made at professional-society meetings, company offices, consortium workshops, and university settings. Papers, including one review paper on ''Reservoir Geophysics'' have been published. Several Master's theses, which will spin off

  5. Crop physiology calibration in CLM

    Directory of Open Access Journals (Sweden)

    I. Bilionis

    2014-10-01

    Full Text Available Farming is using more terrestrial ground, as population increases and agriculture is increasingly used for non-nutritional purposes such as biofuel production. This agricultural expansion exerts an increasing impact on the terrestrial carbon cycle. In order to understand the impact of such processes, the Community Land Model (CLM has been augmented with a CLM-Crop extension that simulates the development of three crop types: maize, soybean, and spring wheat. The CLM-Crop model is a complex system that relies on a suite of parametric inputs that govern plant growth under a given atmospheric forcing and available resources. CLM-Crop development used measurements of gross primary productivity and net ecosystem exchange from AmeriFlux sites to choose parameter values that optimize crop productivity in the model. In this paper we calibrate these parameters for one crop type, soybean, in order to provide a faithful projection in terms of both plant development and net carbon exchange. Calibration is performed in a Bayesian framework by developing a scalable and adaptive scheme based on sequential Monte Carlo (SMC.

  6. Quantitative Molecular Assay for Fingerprinting Microbial Communities of Wastewater and Estrogen-Degrading Consortia

    OpenAIRE

    Yu, Chang-Ping; Ahuja, Rajiv; Sayler, Gary; Chu, Kung-Hui

    2005-01-01

    A quantitative fingerprinting method, called the real-time terminal restriction fragment length polymorphism (real-time-t-RFLP) assay, was developed for simultaneous determination of microbial diversity and abundance within a complex community. The real-time-t-RFLP assay was developed by incorporating the quantitative feature of real-time PCR and the fingerprinting feature of t-RFLP analysis. The assay was validated by using a model microbial community containing three pure strains, an Escher...

  7. Development of a high-throughput G4-FID assay for screening and evaluation of small molecules binding quadruplex nucleic acid structures.

    Science.gov (United States)

    Largy, Eric; Hamon, Florian; Teulade-Fichou, Marie-Paule

    2011-07-01

    G4-FID (G-quadruplex fluorescent intercalator displacement) is a simple and fast method that allows to evaluate the affinity of a compound for G-quadruplex DNA and its selectivity towards duplex DNA. This assay is based on the loss of fluorescence of thiazole orange (TO) upon competitive displacement from DNA by a putative ligand. We describe here the development of a high-throughput version of this assay performed in 96-well microplates, and fully transposable to 384-well microplates. The test was calibrated with a set of G-quadruplex ligands characterized for their ability to bind quadruplex within a large range of affinity. The comparison of the results obtained in microplates and in cuvettes was conducted indicating a full agreement. Additionally, the spectral range of the test was enlarged using two other fluorescent on/off probes whose absorption are red-shifted (TO-PRO-3) and blue-shifted (Hoechst 33258) as compared to that of TO. These labels enable to screen a large diversity of compounds with various optical properties, which was exemplified by evaluation of affinity and selectivity of the porphyrin TMPyP4 that could not be evaluated previously. Altogether, our study demonstrates that the HT-G4-FID assay offers the possibility to label a large variety of G-quadruplexes of biological interest and should enable screening of collections of putative G4-ligands of high structural diversity. It thus represents a powerful tool to bring into light new ligands able to discriminate between quadruplexes of different structures.

  8. Third COS FUV Lifetime Calibration Program: Flatfield and Flux Calibrations

    Science.gov (United States)

    Debes, J. H.; Becker, G.; Roman-Duval, J.; Ely, J.; Massa, D.; Oliveira, C.; Plesha, R.; Proffitt, C.; Taylor, J.

    2016-10-01

    As part of the calibration of the third lifetime position (LP3) of the Cosmic Origins Spectrograph (COS) Far-Ultraviolet (FUV) detector, observations of WD 0308-565 were obtained with the G130M, G160M, and G140L gratings and observations of GD 71 were obtained in the G160M grating through the Point Source Aperture (PSA) to derive low-order flatfields (L-flats) and sensitivities at LP3. Observations were executed for all CENWAVES and all FP-POS with the exception of G130M/1055 and G130M/1096, which remained at LP2. The derivation of the L-flats and sensitivities at LP3 differed from their LP1 and LP2 counterparts in a few key ways, which we describe in this report. Firstly, we quantified a cut-off in spatial frequency that we assigned to the L-flats. Secondly, we derived a new method for simultaneously fitting both the L-flats, pixel-to-pixel flats (P-flats), and sensitvities which we compared to our previous method of separately fitting L-flats and sensitivities. These new methods produce comparable results, but provide us with an external test on the robustness of each approach individually. The results of our work show that with the new profile extraction routines, sensitivities, and L-flats, the relative and absolute flux calibration accuracies (1% and 2% respectively) at LP3 are slightly improved relative to previous locations on the COS FUV detector.

  9. Another look at volume self-calibration: calibration and self-calibration within a pinhole model of Scheimpflug cameras

    Science.gov (United States)

    Cornic, Philippe; Illoul, Cédric; Cheminet, Adam; Le Besnerais, Guy; Champagnat, Frédéric; Le Sant, Yves; Leclaire, Benjamin

    2016-09-01

    We address calibration and self-calibration of tomographic PIV experiments within a pinhole model of cameras. A complete and explicit pinhole model of a camera equipped with a 2-tilt angles Scheimpflug adapter is presented. It is then used in a calibration procedure based on a freely moving calibration plate. While the resulting calibrations are accurate enough for Tomo-PIV, we confirm, through a simple experiment, that they are not stable in time, and illustrate how the pinhole framework can be used to provide a quantitative evaluation of geometrical drifts in the setup. We propose an original self-calibration method based on global optimization of the extrinsic parameters of the pinhole model. These methods are successfully applied to the tomographic PIV of an air jet experiment. An unexpected by-product of our work is to show that volume self-calibration induces a change in the world frame coordinates. Provided the calibration drift is small, as generally observed in PIV, the bias on the estimated velocity field is negligible but the absolute location cannot be accurately recovered using standard calibration data.

  10. Practical assay issues with the PERT/PBRT assay: a highly sensitive reverse transcriptase assay.

    Science.gov (United States)

    Chang, A; Dusing, S

    2006-01-01

    Product safety testing for retroviruses can be achieved by a panel of screening assays, including electron microscopy, viral gene specific PCRs, virus propagation, and detection of reverse transciptase activity. The application of PCR-based reverse transcriptase assays (PERT) that are approximately a million-fold more sensitive than conventional nucleotide incorporation assays in the testing of biologicals is described. Use of PERT assays can be applied to three areas: (i) screening for adventitious retrovirus contamination; (ii) detecting and quantifying endogenous viral particle load and (iii) monitoring levels of infectious retrovirus generation in cell lines that contain endogenous retroviruses.

  11. New method to calibrate a spinner anemometer

    DEFF Research Database (Denmark)

    Demurtas, Giorgio; Friis Pedersen, Troels

    2014-01-01

    The spinner anemometer is a wind sensor, based on three one dimensional sonic sensor probes, mounted on the wind turbine spinner, and an algorithm to convert the wind speeds measured by the three sonic sensors to horizontal wind speed, yaw misalignment and flow inclination angle. The conversion...... to be stopped during calibration in order for the rotor induction not to influence on the calibration, so that the spinner anemometer measures ”free” wind values in stopped condition. The calibration of flow angle measurements is made by calibration of the ratio of the two algorithm constants k2=k1 = k......_. The calibration of k_ is made by relating the spinner anemometer yaw misalignment measurements to the yaw position when yawing the wind turbine in and out of the wind several times. The calibration of the constant k1 is made by comparing the spinner anemometer wind speed measurement with a free metmast or lidar...

  12. Calibration Monitor for Dark Energy Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, M. E.

    2009-11-23

    The goal of this program was to design, build, test, and characterize a flight qualified calibration source and monitor for a Dark Energy related experiment: ACCESS - 'Absolute Color Calibration Experiment for Standard Stars'. This calibration source, the On-board Calibration Monitor (OCM), is a key component of our ACCESS spectrophotometric calibration program. The OCM will be flown as part of the ACCESS sub-orbital rocket payload in addition to monitoring instrument sensitivity on the ground. The objective of the OCM is to minimize systematic errors associated with any potential changes in the ACCESS instrument sensitivity. Importantly, the OCM will be used to monitor instrument sensitivity immediately after astronomical observations while the instrument payload is parachuting to the ground. Through monitoring, we can detect, track, characterize, and thus correct for any changes in instrument senstivity over the proposed 5-year duration of the assembled and calibrated instrument.

  13. Research of Camera Calibration Based on DSP

    Directory of Open Access Journals (Sweden)

    Zheng Zhang

    2013-09-01

    Full Text Available To take advantage of the high-efficiency and stability of DSP in the data processing and the functions of OpenCV library, this study brought forward a scheme that camera calibration in DSP embedded system calibration. An arithmetic of camera calibration based on OpenCV is designed by analyzing the camera model and lens distortion. The transplantation of EMCV to DSP is completed and the arithmetic of camera calibration is migrated and optimized based on the CCS development environment and the DSP/BIOS system. On the premise of realizing calibration function, this arithmetic improves the efficiency of program execution and the precision of calibration and lays the foundation for further research of the visual location based on DSP embedded system.

  14. Herschel SPIRE FTS Relative Spectral Response Calibration

    CERN Document Server

    Fulton, Trevor; Baluteau, Jean-Paul; Benielli, Dominique; Imhof, Peter; Lim, Tanya; Lu, Nanyao; Marchili, Nicola; Naylor, David; Polehampton, Edward; Swinyard, Bruce; Valtchanov, Ivan

    2014-01-01

    Herschel/SPIRE Fourier transform spectrometer (FTS) observations contain emission from both the Herschel Telescope and the SPIRE Instrument itself, both of which are typically orders of magnitude greater than the emission from the astronomical source, and must be removed in order to recover the source spectrum. The effects of the Herschel Telescope and the SPIRE Instrument are removed during data reduction using relative spectral response calibration curves and emission models. We present the evolution of the methods used to derive the relative spectral response calibration curves for the SPIRE FTS. The relationship between the calibration curves and the ultimate sensitivity of calibrated SPIRE FTS data is discussed and the results from the derivation methods are compared. These comparisons show that the latest derivation methods result in calibration curves that impart a factor of between 2 and 100 less noise to the overall error budget, which results in calibrated spectra for individual observations whose n...

  15. Biogeographic calibrations for the molecular clock.

    Science.gov (United States)

    Ho, Simon Y W; Tong, K Jun; Foster, Charles S P; Ritchie, Andrew M; Lo, Nathan; Crisp, Michael D

    2015-09-01

    Molecular estimates of evolutionary timescales have an important role in a range of biological studies. Such estimates can be made using methods based on molecular clocks, including models that are able to account for rate variation across lineages. All clock models share a dependence on calibrations, which enable estimates to be given in absolute time units. There are many available methods for incorporating fossil calibrations, but geological and climatic data can also provide useful calibrations for molecular clocks. However, a number of strong assumptions need to be made when using these biogeographic calibrations, leading to wide variation in their reliability and precision. In this review, we describe the nature of biogeographic calibrations and the assumptions that they involve. We present an overview of the different geological and climatic events that can provide informative calibrations, and explain how such temporal information can be incorporated into dating analyses.

  16. GIFTS SM EDU Radiometric and Spectral Calibrations

    Science.gov (United States)

    Tian, J.; Reisse, R. a.; Johnson, D. G.; Gazarik, J. J.

    2007-01-01

    The Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) Sensor Module (SM) Engineering Demonstration Unit (EDU) is a high resolution spectral imager designed to measure infrared (IR) radiance using a Fourier transform spectrometer (FTS). The GIFTS instrument gathers measurements across the long-wave IR (LWIR), short/mid-wave IR (SMWIR), and visible spectral bands. The raw interferogram measurements are radiometrically and spectrally calibrated to produce radiance spectra, which are further processed to obtain atmospheric profiles via retrieval algorithms. This paper describes the processing algorithms involved in the calibration. The calibration procedures can be subdivided into three categories: the pre-calibration stage, the calibration stage, and finally, the post-calibration stage. Detailed derivations for each stage are presented in this paper.

  17. Radiocarbon calibration - past, present and future

    Energy Technology Data Exchange (ETDEWEB)

    Plicht, J. van der E-mail: plicht@phys.rug.nl

    2004-08-01

    Calibration of the Radiocarbon timescale is traditionally based on tree-rings dated by dendrochronology. At present, the tree-ring curve dates back to about 9900 BC. Beyond this limit, marine datasets extend the present calibration curve INTCAL98 to about 15 600 years ago. Since 1998, a wealth of AMS measurements became available, covering the complete {sup 14}C dating range. No calibration curve can presently be recommended for the older part of the dating range until discrepancies are resolved.

  18. Optical Calibration For Jefferson Lab HKS Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    L. Yuan; L. Tang

    2005-11-04

    In order to accept very forward angle scattering particles, Jefferson Lab HKS experiment uses an on-target zero degree dipole magnet. The usual spectrometer optics calibration procedure has to be modified due to this on-target field. This paper describes a new method to calibrate HKS spectrometer system. The simulation of the calibration procedure shows the required resolution can be achieved from initially inaccurate optical description.

  19. Calibration strategy of CMS electromagnetic calorimeter

    CERN Document Server

    Paramatti, R

    2004-01-01

    Calibration is one of the main factors that set limits on the ultimate performance of the CMS electromagnetic calorimeter at LHC. Crystals raw intercalibration from lab measurements during assembly and CERN-SPS test beam of Supermodules will represent the precalibration at the start-up. In situ calibration with physics events will be the main tool to reduce the constant term to the design goal of 0.5%. The calibration strategy will be described in detail.

  20. Calibration of Avent Wind IRIS SN 01030167

    DEFF Research Database (Denmark)

    Courtney, Michael

    This report presents the result of the lidar calibration performed for a two-beam nacelle based lidar at DTU’s test site for large wind turbines at Høvsøre, Denmark. Calibration is here understood as the establishment of a relation between the reference wind speed measurements with measurement...... uncertainties provided by measurement standard and corresponding lidar wind speed indications with associated measurement uncertainties. The lidar calibration concerns the 10 minute mean wind speed measurements....

  1. Calibration Procedure for 3D Turning Dynamometer

    DEFF Research Database (Denmark)

    Axinte, Dragos Aurelian; Belluci, Walter

    1999-01-01

    The aim of the static calibration of the dynamometer is to obtain the matrix for evaluating cutting forces through the output voltage of the piezoelectric cells and charge amplifiers. In the same time, it is worth to evaluate the linearity of the dependencies between applied forces and output...... of the piezoelectric cells;5. Mounting of the dynamometer;6. Calibration of the dynamometer;7. Data analysis;8. Uncertainty budget of the calibration....

  2. Calibration of Nacelle-based Lidar instrument

    DEFF Research Database (Denmark)

    Yordanova, Ginka; Courtney, Michael

    This report presents the result of the lidar calibration performed for a two-beam nacelle based lidar at DTU’s test site for large wind turbines at Høvsøre, Denmark. Calibration is here understood as the establishment of a relation between the reference wind speed measurements with measurement...... uncertainties provided by measurement standard and corresponding lidar wind speed indications with associated measurement uncertainties. The lidar calibration concerns the 10 minute mean wind speed measurements....

  3. Calibration of Nacelle-based Lidar instrument

    DEFF Research Database (Denmark)

    Georgieva Yankova, Ginka; Courtney, Michael

    This report presents the result of the lidar calibration performed for a four-beam nacelle based lidar at DTU’s test site for large wind turbines at Høvsøre, Denmark.Denmark. Calibration is here understood as the establishment of a relation between the reference wind speed measurements...... with measurement uncertainties provided by measurement standard and corresponding lidar wind speed indications with associated measurement uncertainties. The lidar calibration concerns the 10 minute mean wind speed measurements....

  4. 1987 calibration of the TFTR neutron spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, C.W.; Strachan, J.D. (Los Alamos National Lab., NM (USA); Princeton Univ., NJ (USA). Plasma Physics Lab.)

    1989-12-01

    The {sup 3}He neutron spectrometer used for measuring ion temperatures and the NE213 proton recoil spectrometer used for triton burnup measurements were absolutely calibrated with DT and DD neutron generators placed inside the TFTR vacuum vessel. The details of the detector response and calibration are presented. Comparisons are made to the neutron source strengths measured from other calibrated systems. 23 refs., 19 figs., 6 tabs.

  5. Observatory Magnetometer In-Situ Calibration

    Directory of Open Access Journals (Sweden)

    A Marusenkov

    2011-07-01

    Full Text Available An experimental validation of the in-situ calibration procedure, which allows estimating parameters of observatory magnetometers (scale factors, sensor misalignment without its operation interruption, is presented. In order to control the validity of the procedure, the records provided by two magnetometers calibrated independently in a coil system have been processed. The in-situ estimations of the parameters are in very good agreement with the values provided by the coil system calibration.

  6. MULTIPLE ELECTRONIC CONTROL UNITS CALIBRATION SYSTEM BASED ON EXPLICIT CALIBRATION PROTOCOL AND J1939 PROTOCOL

    Institute of Scientific and Technical Information of China (English)

    YANG Shiwei; ZHU Keqing; XU Quankui; YANG Lin; ZHUO Bin

    2008-01-01

    The rising number of electronic control units (ECUs) in vehicles and the decreasing time to market have led to the need for advanced methods of calibration. A multi-ECU calibration system was developed based on the explicit calibration protocol (XCP) and J1939 communication protocol to satisfy the need of calibrating multiple ECUs simultaneously. The messages in the controller area network (CAN) are defined in the J1939 protocol. Each CAN node can get its own calibration messages and information from other ECUs, and block other messages by qualifying the CAN messages with priority, source or destination address. The data field of the calibration message is designed with the XCP , with CAN acting as the transport layer. The calibration sessions are setup with the event-triggered XCP driver in the master node and the responding XCP driver in the slave nodes. Mirroring calibration variables from ROM to RAM enables the user to calibrate ECUs online. The application example shows that the multi-ECU calibration system can calibrate multiple ECUs simultaneously, and the main program can also accomplish its calculation and send commands to the actuators in time. By the multi-ECU calibration system, the calibration effort and time can be reduced and the variables in ECU can get a better match with the variables of other ECUs.

  7. Sloan Digital Sky Survey Photometric Calibration Revisited

    Science.gov (United States)

    Marriner, J.

    2016-05-01

    The Sloan Digital Sky Survey calibration is revisited to obtain the most accurate photometric calibration. A small but significant error is found in the flat-fielding of the Photometric telescope used for calibration. Two SDSS star catalogs are compared and the average difference in magnitude as a function of right ascension and declination exhibits small systematic errors in relative calibration. The photometric transformation from the SDSS Photometric Telescope to the 2.5 m telescope is recomputed and compared to synthetic magnitudes computed from measured filter bandpasses.

  8. The Second VLBA Calibrator Survey: VCS2

    Science.gov (United States)

    Fomalont, E. B.; Petrov, L.; MacMillan, D. S.; Gordon, D.; Ma, C.

    2003-11-01

    This paper presents an extension of the Very Long Baseline Array Calibrator Survey, called VCS2, containing 276 sources. This survey fills in regions of the sky that were not completely covered by the previous VCS1 calibrator survey. The VCS2 survey includes calibrator sources near the Galactic plane, -30deganalysis of the group delays measured at 2.3 and 8.4 GHz using the Goddard Space Flight Center CALC/SOLVE package. From the VLBA snapshot observations, images of the calibrators are available, and each source is given a quality code for anticipated use. The VCS2 catalog is available from the NRAO Web site.

  9. Cross-calibration of interferometric SAR data

    DEFF Research Database (Denmark)

    Dall, Jørgen

    2003-01-01

    Generation of digital elevation models from interferometric synthetic aperture radar (SAR) data is a well established technique. Achieving a high geometric fidelity calls for a calibration accounting for inaccurate navigation data and system parameters as well as system imperfections. Fully......, but not necessarily from map to map. It is based on natural distributed targets for which no a priori knowledge is needed. In particular, no DEM is required as in calibration techniques based on dedicated calibration scenes. To achieve absolute calibration, i.e. elimination of a constant elevation offset, a single...

  10. Sloan Digital Sky Survey Photometric Calibration Revisited

    Energy Technology Data Exchange (ETDEWEB)

    Marriner, John; /Fermilab

    2012-06-29

    The Sloan Digital Sky Survey calibration is revisited to obtain the most accurate photometric calibration. A small but significant error is found in the flat-fielding of the Photometric telescope used for calibration. Two SDSS star catalogs are compared and the average difference in magnitude as a function of right ascension and declination exhibits small systematic errors in relative calibration. The photometric transformation from the SDSS Photometric Telescope to the 2.5 m telescope is recomputed and compared to synthetic magnitudes computed from measured filter bandpasses.

  11. FY2008 Calibration Systems Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Cannon, Bret D.; Myers, Tanya L.; Broocks, Bryan T.

    2009-01-01

    The Calibrations project has been exploring alternative technologies for calibration of passive sensors in the infrared (IR) spectral region. In particular, we have investigated using quantum cascade lasers (QCLs) because these devices offer several advantages over conventional blackbodies such as reductions in size and weight while providing a spectral source in the IR with high output power. These devices can provide a rapid, multi-level radiance scheme to fit any nonlinear behavior as well as a spectral calibration that includes the fore-optics, which is currently not available for on-board calibration systems.

  12. The long term stability of lidar calibrations

    DEFF Research Database (Denmark)

    Courtney, Michael; Gayle Nygaard, Nicolai

    Wind lidars are now used extensively for wind resource measurements. One of the requirements for the data to be accepted in support of project financing (so-called ‘banka-bility’) is to demonstrate the long-term stability of lidar cali-brations. Calibration results for six Leosphere WindCube li-dars......-ters pertaining in the different calibration periods. This is supported by sliding-window analyses of one lidar at one location where the same order of variation is observed as between pre-service and post-service calibrations....

  13. Calibration services for medical applications of radiation

    Energy Technology Data Exchange (ETDEWEB)

    DeWerd, L.A.

    1993-12-31

    Calibration services for the medical community applications of radiation involve measuring radiation precisely and having traceability to the National Institute of Standards and Technology (NIST). Radiation therapy applications involve the use of ionization chambers and electrometers for external beams and well-type ionization chamber systems as well as radioactive sources for brachytherapy. Diagnostic x-ray applications involve ionization chamber systems and devices to measure other parameters of the x-ray machine, such as non-invasive kVp meters. Calibration laboratories have been established to provide radiation calibration services while maintaining traceability to NIST. New radiation applications of the medical community spur investigation to provide the future calibration needs.

  14. TOF PET offset calibration from clinical data

    Science.gov (United States)

    Werner, M. E.; Karp, J. S.

    2013-06-01

    In this paper, we present a timing calibration technique for time-of-flight positron emission tomography (TOF PET) that eliminates the need for a specialized data acquisition. By eliminating the acquisition, the process becomes fully automated, and can be performed with any clinical data set and whenever computing resources are available. It also can be applied retroactively to datasets for which a TOF offset calibration is missing or suboptimal. Since the method can use an arbitrary data set to perform a calibration prior to a TOF reconstruction, possibly of the same data set, one also can view this as reconstruction from uncalibrated data. We present a performance comparison with existing calibration techniques.

  15. Calibration of ACS Prism Slitless Spectroscopy Modes

    CERN Document Server

    Larsen, S S; Walsh, J R

    2005-01-01

    The Advanced Camera for Surveys is equipped with three prisms in the Solar Blind (SBC) and High Resolution (HRC) Channels, which together cover the 1150 - 3500 A range, albeit at highly non-uniform spectral resolution. We present new wavelength- and flux calibrations of the SBC (PR110L and PR130L) and HRC (PR200L) prisms, based on calibration observations obtained in Cycle 13. The calibration products are available to users via the ST-ECF/aXe web pages, and can be used directly with the aXe package. We discuss our calibration strategy and some caveats specific to slitless prism spectroscopy.

  16. Absolute calibration of the Auger fluorescence detectors

    Energy Technology Data Exchange (ETDEWEB)

    Bauleo, P.; Brack, J.; Garrard, L.; Harton, J.; Knapik, R.; Meyhandan, R.; Rovero, A.C.; /Buenos Aires, IAFE; Tamashiro, A.; Warner, D.

    2005-07-01

    Absolute calibration of the Pierre Auger Observatory fluorescence detectors uses a light source at the telescope aperture. The technique accounts for the combined effects of all detector components in a single measurement. The calibrated 2.5 m diameter light source fills the aperture, providing uniform illumination to each pixel. The known flux from the light source and the response of the acquisition system give the required calibration for each pixel. In the lab, light source uniformity is studied using CCD images and the intensity is measured relative to NIST-calibrated photodiodes. Overall uncertainties are presently 12%, and are dominated by systematics.

  17. Gearbox Reliability Collaborative Bearing Calibration

    Energy Technology Data Exchange (ETDEWEB)

    van Dam, J.

    2011-10-01

    NREL has initiated the Gearbox Reliability Collaborative (GRC) to investigate the root cause of the low wind turbine gearbox reliability. The GRC follows a multi-pronged approach based on a collaborative of manufacturers, owners, researchers and consultants. The project combines analysis, field testing, dynamometer testing, condition monitoring, and the development and population of a gearbox failure database. At the core of the project are two 750kW gearboxes that have been redesigned and rebuilt so that they are representative of the multi-megawatt gearbox topology currently used in the industry. These gearboxes are heavily instrumented and are tested in the field and on the dynamometer. This report discusses the bearing calibrations of the gearboxes.

  18. A Cryogenic Infrared Calibration Target

    Science.gov (United States)

    Wollack, E. J.; Kinzer, R. E., Jr.; Rinehart, S. A.

    2014-01-01

    A compact cryogenic calibration target is presented that has a peak diffuse reflectance, R < or = 0.003, from 800 to 4800/cm (12 - 2 microns ). Upon expanding the spectral range under consideration to 400-10,000/ cm-1 (25 - 1 microns) the observed performance gracefully degrades to R < or = 0.02 at the band edges. In the implementation described, a high-thermal-conductivity metallic substrate is textured with a pyramidal tiling and subsequently coated with a thin lossy dielectric coating that enables high absorption and thermal uniformity across the target. The resulting target assembly is lightweight, has a low-geometric profile, and has survived repeated thermal cycling from room temperature to approx.4 K. Basic design considerations, governing equations, and test data for realizing the structure described are provided. The optical properties of selected absorptive materials-Acktar Fractal Black, Aeroglaze Z306, and Stycast 2850 FT epoxy loaded with stainless steel powder-are characterized and presented

  19. Metrology - Beyond the Calibration Lab

    Science.gov (United States)

    Mimbs, Scott M.

    2008-01-01

    We rely on data from measurements every day; a gas-pump, a speedometer, and a supermarket weight scale are just three examples of measurements we use to make decisions. We generally accept the data from these measurements as "valid." One reason we can accept the data is the "legal metrology" requirements established and regulated by the government in matters of commerce. The measurement data used by NASA, other government agencies, and industry can be critical to decisions which affect everything from economic viability, to mission success, to the security of the nation. Measurement data can even affect life and death decisions. Metrology requirements must adequately provide for risks associated with these decisions. To do this, metrology must be integrated into all aspects of an industry including research, design, testing, and product acceptance. Metrology, the science of measurement, has traditionally focused on the calibration of instruments, and although instrument calibration is vital, it is only a part of the process that assures quality in measurement data. For example, measurements made in research can influence the fundamental premises that establish the design parameters, which then flow down to the manufacturing processes, and eventually impact the final product. Because a breakdown can occur anywhere within this cycle, measurement quality assurance has to be integrated into every part of the life-cycle process starting with the basic research and ending with the final product inspection process. The purpose of this paper is to discuss the role of metrology in the various phases of a product's life-cycle. For simplicity, the cycle will be divided in four broad phases, with discussions centering on metrology within NASA. .

  20. Assay of Endocannabinoid Oxidation by Cyclooxygenase-2

    Science.gov (United States)

    Kudalkar, Shalley N.; Kingsley, Philip J.; Marnett, Lawrence J.

    2017-01-01

    Summary The endocannabinoids, 2-arachidonoylglycerol (2-AG) and arachidonylethanolamide (AEA) are endogenous ligands for the cannabinoid receptors (CB1 and CB2) and are implicated in a wide array of physiological processes. These neutral arachidonic acid (AA) derivatives have been identified as efficient substrates for the second isoform of the cyclooxygenase enzyme (COX-2). A diverse family of prostaglandin glycerol esters (PG-Gs) and prostaglandin ethanolamides (PG-EAs) is generated by the action of COX-2 (and downstream prostaglandin synthases) on 2-AG and AEA. As the biological importance of the endocannabinoid system becomes more apparent, there is a tremendous need for robust, sensitive and efficient analytical methodology for the endocannabinoids and their metabolites. In this chapter we describe methodology suitable for carrying out oxygenation of endocannabinoids by COX-2, and analysis of products of endocannabinoid oxygenation by COX-2 and of endocannabinoids themselves from in-vitro and cell assays. PMID:27245906

  1. Simple transfer calibration method for a Cimel Sun-Moon photometer: calculating lunar calibration coefficients from Sun calibration constants.

    Science.gov (United States)

    Li, Zhengqiang; Li, Kaitao; Li, Donghui; Yang, Jiuchun; Xu, Hua; Goloub, Philippe; Victori, Stephane

    2016-09-20

    The Cimel new technologies allow both daytime and nighttime aerosol optical depth (AOD) measurements. Although the daytime AOD calibration protocols are well established, accurate and simple nighttime calibration is still a challenging task. Standard lunar-Langley and intercomparison calibration methods both require specific conditions in terms of atmospheric stability and site condition. Additionally, the lunar irradiance model also has some known limits on its uncertainty. This paper presents a simple calibration method that transfers the direct-Sun calibration constant, V0,Sun, to the lunar irradiance calibration coefficient, CMoon. Our approach is a pure calculation method, independent of site limits, e.g., Moon phase. The method is also not affected by the lunar irradiance model limitations, which is the largest error source of traditional calibration methods. Besides, this new transfer calibration approach is easy to use in the field since CMoon can be obtained directly once V0,Sun is known. Error analysis suggests that the average uncertainty of CMoon over the 440-1640 nm bands obtained with the transfer method is 2.4%-2.8%, depending on the V0,Sun approach (Langley or intercomparison), which is comparable with that of lunar-Langley approach, theoretically. In this paper, the Sun-Moon transfer and the Langley methods are compared based on site measurements in Beijing, and the day-night measurement continuity and performance are analyzed.

  2. Clustered Calibration: An Improvement to Radio Interferometric Direction Dependent Self-Calibration

    CERN Document Server

    Kazemi, Sanaz; Zaroubi, Saleem

    2013-01-01

    The new generation of radio synthesis arrays, such as LOFAR and SKA, have been designed to surpass existing arrays in terms of sensitivity, angular resolution and frequency coverage. This evolution has led to the development of advanced calibration techniques that ensure the delivery of accurate results at the lowest possible computational cost. However, the performance of such calibration techniques is still limited by the compact, bright sources in the sky, used as calibrators. It is important to have a bright enough source that is well distinguished from the background noise level in order to achieve satisfactory results in calibration. We present "clustered calibration" as a modification to traditional radio interferometric calibration, in order to accommodate faint sources that are almost below the background noise level into the calibration process. The main idea is to employ the information of the bright sources' measured signals as an aid to calibrate fainter sources that are nearby the bright sources...

  3. Design and Calibration of a Cryogenic Blackbody Calibrator at Centimeter Wavelengths

    CERN Document Server

    Kogut, A J; Fixsen, D J; Limon, M; Mirel, P G A; Levin, S; Seiffert, M; Lubin, P M

    2004-01-01

    We describe the design and calibration of an external cryogenic blackbody calibrator used for the first two flights of the Absolute Radiometer for Cosmology, Astrophysics, and Diffuse Emission (ARCADE) instrument. The calibrator consists of a microwave absorber weakly coupled to a superfluid liquid helium bath. Half-wave corrugations viewed 30 deg off axis reduce the return loss below -35 dB. Ruthenium oxide resistive thermometers embedded within the absorber monitor the temperature across the face of the calibrator. The thermal calibration transfers the calibration of a reference thermometer to the flight thermometers using the flight thermometer readout system. Data taken near the superfluid transition in 8 independent calibrations 4 years apart agree within 0.3 mK, providing an independent verification of the thermometer calibration at temperatures near that of the cosmic microwave background.

  4. Transporter assays and assay ontologies: useful tools for drug discovery.

    Science.gov (United States)

    Zdrazil, Barbara; Chichester, Christine; Zander Balderud, Linda; Engkvist, Ola; Gaulton, Anna; Overington, John P

    2014-06-01

    Transport proteins represent an eminent class of drug targets and ADMET (absorption, distribution, metabolism, excretion, toxicity) associated genes. There exists a large number of distinct activity assays for transport proteins, depending on not only the measurement needed (e.g. transport activity, strength of ligand–protein interaction), but also due to heterogeneous assay setups used by different research groups. Efforts to systematically organize this (divergent) bioassay data have large potential impact in Public-Private partnership and conventional commercial drug discovery. In this short review, we highlight some of the frequently used high-throughput assays for transport proteins, and we discuss emerging assay ontologies and their application to this field. Focusing on human P-glycoprotein (Multidrug resistance protein 1; gene name: ABCB1, MDR1), we exemplify how annotation of bioassay data per target class could improve and add to existing ontologies, and we propose to include an additional layer of metadata supporting data fusion across different bioassays.

  5. Comparative endpoint sensitivity of in vitro estrogen agonist assays.

    Science.gov (United States)

    Dreier, David A; Connors, Kristin A; Brooks, Bryan W

    2015-07-01

    Environmental and human health implications of endocrine disrupting chemicals (EDCs), particularly xenoestrogens, have received extensive study. In vitro assays are increasingly employed as diagnostic tools to comparatively evaluate chemicals, whole effluent toxicity and surface water quality, and to identify causative EDCs during toxicity identification evaluations. Recently, the U.S. Environmental Protection Agency (USEPA) initiated ToxCast under the Tox21 program to generate novel bioactivity data through high throughput screening. This information is useful for prioritizing chemicals requiring additional hazard information, including endocrine active chemicals. Though multiple in vitro and in vivo techniques have been developed to assess estrogen agonist activity, the relative endpoint sensitivity of these approaches and agreement of their conclusions remain unclear during environmental diagnostic applications. Probabilistic hazard assessment (PHA) approaches, including chemical toxicity distributions (CTD), are useful for understanding the relative sensitivity of endpoints associated with in vitro and in vivo toxicity assays by predicting the likelihood of chemicals eliciting undesirable outcomes at or above environmentally relevant concentrations. In the present study, PHAs were employed to examine the comparative endpoint sensitivity of 16 in vitro assays for estrogen agonist activity using a diverse group of compounds from the USEPA ToxCast dataset. Reporter gene assays were generally observed to possess greater endpoint sensitivity than other assay types, and the Tox21 ERa LUC BG1 Agonist assay was identified as the most sensitive in vitro endpoint for detecting an estrogenic response. When the sensitivity of this most sensitive ToxCast in vitro endpoint was compared to the human MCF-7 cell proliferation assay, a common in vitro model for biomedical and environmental monitoring applications, the ERa LUC BG1 assay was several orders of magnitude less

  6. Does staff diversity imply openness to diversity?

    DEFF Research Database (Denmark)

    Lauring, Jakob; Selmer, Jan

    2013-01-01

    Purpose – Post-secondary educational organizations are currently some of the most diverse settings to be found. However, few educational studies have dealt with staff diversity and hardly any has looked outside the USA. The purpose of this paper is to present a study of members of international u...

  7. CERN Diversity Newsletter - March 2017

    CERN Document Server

    Guinot, Genevieve; CERN. Geneva. HR Department

    2017-01-01

    The CERN Diversity Newsletter, informing on recent and ongoing diversity activities, and interesting reads, videos and other links related to diversity. Subscribe here: https://diversity.web.cern.ch/2015/07/subscribe-diversity-newsletter

  8. CERN Diversity Newsletter - September 2016

    CERN Document Server

    Guinot, Genevieve

    2016-01-01

    Quarterly CERN Diversity Newsletter, informing on recent and ongoing diversity activities, and interesting reads, videos and other links related to diversity. Subscribe here: https://diversity.web.cern.ch/2015/07/subscribe-diversity-newsletter

  9. CERN Diversity Newsletter - November 2015

    CERN Document Server

    Kaltenhauser, Kristin; CERN. Geneva. HR Department

    2015-01-01

    Quarterly CERN Diversity Newsletter, informing on recent and ongoing diversity activities, and interesting reads, videos and other links related to diversity. Subscribe here: https://diversity.web.cern.ch/2015/07/subscribe-diversity-newsletter

  10. CERN Diversity Newsletter - March 2016

    CERN Document Server

    Kaltenhauser, Kristin; CERN. Geneva. HR Department

    2016-01-01

    Quarterly CERN Diversity Newsletter, informing on recent and ongoing diversity activities, and interesting reads, videos and other links related to diversity. Subscribe here: https://diversity.web.cern.ch/2015/07/subscribe-diversity-newsletter

  11. Validation and application of an assay for deoxyribonucleic acid to estimate concentrations of bull sperm.

    Science.gov (United States)

    Fenton, S E; Ax, R L; Cowan, C M; Coyle, T; Gilbert, G R; Lenz, R W

    1990-11-01

    Spectrophotometers are used for estimating sperm concentrations from raw ejaculates in semen processing laboratories. Unfortunately, these instruments have a limited detection spectrum and do not permit accurate quantification of sperm numbers in highly diluted or concentrated samples. The objectives of this study were to validate a DNA assay for quantification of sperm numbers in extended or undiluted semen samples and to determine precision of the assay. The principle of the assay is based upon a fluorescent dye that binds to adenine-thymine base pairs in double-stranded DNA. Semen samples and calf thymus DNA standards were sonicated in 2 M NaCl buffer with 1 mM EDTA. The DNA content of samples was compared to standards of calf thymus DNA using fluorometry. Sensitivity of the assay was determined to be 1.4 x 10(5) sperm cells. Concentrations of sperm estimated from DNA assay values did not differ from flow cytometric cell counts. Assays were performed in three different laboratories, using different equipment, to assess the assay's repeatability. Estimates of sperm concentrations determined by the DNA assay were similar, regardless of location and source of equipment used to perform the assays. This assay fulfills statistical criteria for being sensitive, accurate, and repeatable, and it can be employed in laboratories processing semen for artificial insemination as a tool for spectrophotometer calibration, a check for straw filling accuracy, or to quantify sperm numbers in extended, packaged semen.

  12. Radiocarbon calibration - past, present and future

    NARCIS (Netherlands)

    van der Plicht, J

    2004-01-01

    Calibration of the Radiocarbon timescale is traditionally based on tree-rings dated by dendrochronology. At present, the tree-ring curve dates back to about 9900 BC. Beyond this limit, marine datasets extend the present calibration curve INTCAL98 to about 15600 years ago. Since 1998, a wealth of AMS

  13. Interferometric Calibration with Natural Distributed Targets

    DEFF Research Database (Denmark)

    Dall, Jørgen; Christensen, Erik Lintz

    2002-01-01

    Cross-calibration is a fully automated algorithm for calibration of interferometric synthetic aperture radar (IFSAR) data. It has been developed for single-pass interferometry, but the principles may be applicable to multi-pass interferometry, too. The algorithm is based on natural distributed...

  14. Calibration of Ground-based Lidar instrument

    DEFF Research Database (Denmark)

    Villanueva, Héctor; Gómez Arranz, Paula

    This report presents the result of the lidar calibration performed for the given Ground-based Lidar at DTU’s test site for large wind turbines at Høvsøre, Denmark. Calibration is here understood as the establishment of a relation between the reference wind speed measurements with measurement unce...

  15. Calibration of Ground -based Lidar instrument

    DEFF Research Database (Denmark)

    Villanueva, Héctor; Yordanova, Ginka

    This report presents the result of the lidar calibration performed for the given Ground-based Lidar at DTU’s test site for large wind turbines at Høvsøre, Denmark. Calibration is here understood as the establishment of a relation between the reference wind speed measurements with measurement unce...

  16. Planck 2013 results. V. LFI calibration

    DEFF Research Database (Denmark)

    Planck Collaboration,; Aghanim, N.; Armitage-Caplan, C.;

    2014-01-01

    We discuss the methods employed to photometrically calibrate the data acquired by the Low Frequency Instrument on Planck. Our calibration is based on the Solar Dipole, caused by motion of the Solar System with respect to the CMB rest frame, which provides a signal of a few mK with the same spectr...

  17. Sky camera geometric calibration using solar observations

    Science.gov (United States)

    Urquhart, Bryan; Kurtz, Ben; Kleissl, Jan

    2016-09-01

    A camera model and associated automated calibration procedure for stationary daytime sky imaging cameras is presented. The specific modeling and calibration needs are motivated by remotely deployed cameras used to forecast solar power production where cameras point skyward and use 180° fisheye lenses. Sun position in the sky and on the image plane provides a simple and automated approach to calibration; special equipment or calibration patterns are not required. Sun position in the sky is modeled using a solar position algorithm (requiring latitude, longitude, altitude and time as inputs). Sun position on the image plane is detected using a simple image processing algorithm. The performance evaluation focuses on the calibration of a camera employing a fisheye lens with an equisolid angle projection, but the camera model is general enough to treat most fixed focal length, central, dioptric camera systems with a photo objective lens. Calibration errors scale with the noise level of the sun position measurement in the image plane, but the calibration is robust across a large range of noise in the sun position. Calibration performance on clear days ranged from 0.94 to 1.24 pixels root mean square error.

  18. Lidar to lidar calibration phase 2

    DEFF Research Database (Denmark)

    Yordanova, Ginka; Courtney, Michael

    This report presents the results from phase 2 of a lidar to lidar (L2L) calibration procedure. Phase two of the project included two measurement campaigns conducted at given sites. The purpose was to find out if the lidar-to-lidar calibration procedure can be conducted with similar results...

  19. Calibration procedure for fire resistance furnaces

    NARCIS (Netherlands)

    Twilt, L.; Leur, P.H.E. van de; Wickström, U.

    1996-01-01

    On behalf of CEN/TC 127 "Fire Safety in Buildings", a series of tests has been carried out to evaluate and complete the draft calibration procedure for fire resistance furnaces [4]. Fourteen laboratories in nine European countries participated in the test series, each carrying out one calibration te

  20. Building X-ray Diffraction Calibration Software

    Energy Technology Data Exchange (ETDEWEB)

    Lande, Joshua; /Marlboro Coll.

    2007-10-31

    X-ray diffraction is a technique used to analyze the structure of crystals. It records the interference pattern created when x-rays travel through a crystal. Three dimensional structure can be inferred from these two dimensional diffraction patterns. Before the patterns can be analyzed, diffraction data must be precisely calibrated. Calibration is used to determine the experimental parameters of the particular experiment. This is done by fitting the experimental parameters to the diffraction pattern of a well understood crystal. Fit2D is a software package commonly used to do this calibration but it leaves much to be desired. In particular, it does not give very much control over the calibration of the data, requires a significant amount of manual input, does not allow for the calibration of highly tilted geometries, does not properly explain the assumptions that it is making, and cannot be modified. We build code to do this calibration while at the same time overcoming the limitations of Fit2D. This paper describes the development of the calibration software and the assumptions that are made in doing the calibration.

  1. Planck 2015 results: V. LFI calibration

    DEFF Research Database (Denmark)

    Ade, P. A R; Aghanim, N.; Ashdown, M.;

    2016-01-01

    We present a description of the pipeline used to calibrate the Planck Low Frequency Instrument (LFI) timelines into thermodynamic temperatures for the Planck 2015 data release, covering four years of uninterrupted operations. As in the 2013 data release, our calibrator is provided by the spin-syn...

  2. Troponin assays in the assessment of the equine myocardium.

    Science.gov (United States)

    Rossi, T M; Pyle, W G; Maxie, M G; Pearl, D L; Physick-Sheard, P W

    2014-05-01

    In 2000, troponin assays were adopted as the test of choice for detection of myocardial injury in man. This decision was made after extensive testing and followed a 60 year search for a biomarker of myocardial damage with sufficient analytical sensitivity and specificity. This has led to proliferation of assays for use in human medicine, each requiring extensive testing and validation before it could be made available on the open market for human use. The search for ever-more analytically sensitive assays and for a standard reference material continues. The adoption of troponin testing in veterinary medicine followed shortly after its development for use in man, providing a much-needed means of detecting and monitoring myocardial damage in horses. However, application of these tests in veterinary medicine has exclusively involved use of assays designed for and clinically validated in human patients. There is no mandated requirement for test validation in veterinary medicine and, while many of these assays have been shown to be capable of detecting equine troponin, the wide diversity of available tests, lack of validation, absence of protocols for their use and lack of standardisation make their application problematic. The objective of this review article is to address this issue, offering guidance where data are available and encouraging caution where there are none. Ultimately, the overall goal of this review is to examine critically the use of troponin assays in the horse and to promote the accurate and appropriate interpretation of valid results.

  3. CERN Radiation Protection (RP) calibration facilities

    CERN Document Server

    AUTHOR|(CDS)2082069; Macián-Juan, Rafael

    Radiation protection calibration facilities are essential to ensure the correct operation of radiation protection instrumentation. Calibrations are performed in specific radiation fields according to the type of instrument to be calibrated: neutrons, photons, X-rays, beta and alpha particles. Some of the instruments are also tested in mixed radiation fields as often encountered close to high-energy particle accelerators. Moreover, calibration facilities are of great importance to evaluate the performance of prototype detectors; testing and measuring the response of a prototype detector to well-known and -characterized radiation fields contributes to improving and optimizing its design and capabilities. The CERN Radiation Protection group is in charge of performing the regular calibrations of all CERN radiation protection devices; these include operational and passive dosimeters, neutron and photon survey-meters, and fixed radiation detectors to monitor the ambient dose equivalent, H*(10), inside CERN accelera...

  4. Parallel Calibration for Sensor Array Radio Interferometers

    CERN Document Server

    Brossard, Martin; Pesavento, Marius; Boyer, Rémy; Larzabal, Pascal; Wijnholds, Stefan J

    2016-01-01

    In order to meet the theoretically achievable imaging performance, calibration of modern radio interferometers is a mandatory challenge, especially at low frequencies. In this perspective, we propose a novel parallel iterative multi-wavelength calibration algorithm. The proposed algorithm estimates the apparent directions of the calibration sources, the directional and undirectional complex gains of the array elements and their noise powers, with a reasonable computational complexity. Furthermore, the algorithm takes into account the specific variation of the aforementioned parameter values across wavelength. Realistic numerical simulations reveal that the proposed scheme outperforms the mono-wavelength calibration scheme and approaches the derived constrained Cram\\'er-Rao bound even with the presence of non-calibration sources at unknown directions, in a computationally efficient manner.

  5. Calibration biases in logical reasoning tasks

    Directory of Open Access Journals (Sweden)

    Guillermo Macbeth

    2013-08-01

    Full Text Available The aim of this contribution is to present an experimental study about calibration in deductive reasoning tasks. Calibration is defi ned as the empirical convergence or divergence between the objective and the subjective success. The underconfi dence bias is understood as the dominance of the former over the latter. The hypothesis of this study states that the form of the propositions presented in the experiment is critical for calibration phenomena. Affi rmative and negative propositions are distinguished in their cognitive processing. Results suggests that monotonous compound propositions are prone to underconfi dence. An heuristic approach to this phenomenon is proposed. The activation of a monotony heuristic would produce an illusion of simplicity that generates the calibration bias. These evidence is analysed in the context of the metacognitive modeling of calibration phenomena.

  6. Electromagnetic Calorimeter Calibration with $\\pi^{0}$

    CERN Multimedia

    Puig Navarro, A

    2009-01-01

    Several methods can be used in order to achieve precise calibration of the LHCb Electromagnetic Calorimeter (ECAL) once reasonable cell equalization has been reached. At low transverse energy, the standard calibration procedure is an iterative method based on the fit of the $\\gamma\\gamma$ invariant mass distribution for each cell of the decay $\\pi^{0}\\to\\gamma\\gamma$ with resolved photons. A new technique for generating the combinatorial background of such decays directly from data has been developed. Knowledge of the background could allow an alternative calibration method based on a event by event fit of the same $\\gamma\\gamma$ invariant mass distribution where contributions from groups of cells are considered in a single fit. The background generation procedure and this possible new calibration method are presented in this poster, in addition to an overview of the LHCb Calorimetry system and ECAL calibration techniques.

  7. Optimal Calibration Accuracy for Gravitational Wave Detectors

    CERN Document Server

    Lindblom, Lee

    2009-01-01

    Calibration errors in the response function of a gravitational wave detector degrade its ability to detect and then to measure the properties of any detected signals. This paper derives the needed levels of calibration accuracy for each of these data-analysis tasks. The levels derived here are optimal in the sense that lower accuracy would result in missed detections and/or a loss of measurement precision, while higher accuracy would be made irrelevant by the intrinsic noise level of the detector. Calibration errors affect the data-analysis process in much the same way as errors in theoretical waveform templates. The optimal level of calibration accuracy is expressed therefore as a joint limit on modeling and calibration errors: increased accuracy in one reduces the accuracy requirement in the other.

  8. Absolute sensitivity calibration of extreme ultraviolet photoresists

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Juanita; Naulleau, Patrick P.; Gullikson, Eric M.; Aquila, Andrew; George, Simi; Niakoula, Dimitra

    2008-05-16

    One of the major challenges facing the commercialization of extreme ultraviolet (EUV) lithography remains simultaneously achieving resist sensitivity, line-edge roughness, and resolution requirement. Sensitivity is of particular concern owing to its direct impact on source power requirements. Most current EUV exposure tools have been calibrated against a resist standard with the actual calibration of the standard resist dating back to EUV exposures at Sandia National Laboratories in the mid 1990s. Here they report on an independent sensitivity calibration of two baseline resists from the SEMATECH Berkeley MET tool performed at the Advanced Light Source Calibrations and Standards beamline. The results show the baseline resists to be approximately 1.9 times faster than previously thought based on calibration against the long standing resist standard.

  9. Boeing infrared sensor (BIRS) calibration facility

    Science.gov (United States)

    Hazen, John D.; Scorsone, L. V.

    1990-01-01

    The Boeing Infrared Sensor (BIRS) Calibration Facility represents a major capital investment in optical and infrared technology. The facility was designed and built for the calibration and testing of the new generation large aperture long wave infrared (LWIR) sensors, seekers, and related technologies. Capability exists to perform both radiometric and goniometric calibrations of large infrared sensors under simulated environmental operating conditions. The system is presently configured for endoatmospheric calibrations with a uniform background field which can be set to simulate the expected mission background levels. During calibration, the sensor under test is also exposed to expected mission temperatures and pressures within the test chamber. Capability exists to convert the facility for exoatmospheric testing. The configuration of the system is described along with hardware elements and changes made to date are addressed.

  10. The calibration of the vector polarimeter POLIS

    CERN Document Server

    Beck, C

    2013-01-01

    In this diploma thesis, the calibration of the vector polarimeter POLIS will be described. The instrument is built by the Kiepenheuer-Institut fuer Sonnenphysik (Freiburg/Germany) in cooperation with the High Altitude Observatory (Boulder/USA) and will be operated at the German Vacuum Tower Telescope in Tenerife. The instrument yields simultaneously the polarization state of light in two spectral ranges at 396 nm and 630 nm. The measurement is performed with a rotating retarder, which modulates the incident polarization. The modulation is transformed into a varying intensity through polarizing beamsplitters. The demodulation uses a weighted integration scheme to obtain the full Stokes vector of the radiation. The calibration of the polarimeter is performed through the evaluation of a calibration data set produced with a calibration unit consisting of a linear polarizer and a retarder. The instrumental calibration and the polarimetric model of the telescope are described in detail. This document is an unaltere...

  11. DECal: A Spectrophotometric Calibration System For DECam

    CERN Document Server

    Marshall, J L; DePoy, D L; Prochaska, Travis; Allen, Richard; Behm, Tyler W; Martin, Emily C; Veal, Brannon; Villanueva,, Steven; Williams, Patrick; Wise, Jason

    2013-01-01

    DECal is a new calibration system for the CTIO 4 m Blanco telescope. It is currently being installed as part of the Dark Energy Survey and will provide both broadband flat fields and narrowband (about 1 nm bandwidth) spectrophotometric calibration for the new Dark Energy Camera (DECam). Both of these systems share a new Lambertian flat field screen. The broadband flat field system uses LEDs to illuminate each photometric filter. The spectrophotometric calibration system consists of a monochromator-based tunable light source that is projected onto the flat field screen using a custom line-to-spot fiber bundle and an engineered diffuser. Several calibrated photodiodes positioned along the beam monitor the telescope throughput as a function of wavelength. This system will measure the wavelength-dependent instrumental response function of the total telescope+instrument system in the range 300 < lambda < 1100nm. The spectrophotometric calibration will be performed regularly (roughly once per month) to determ...

  12. Calibration concepts for the MUSE integral field

    Science.gov (United States)

    Kelz, Andreas; Bauer, Svend M.; Roth, Martin M.

    2006-06-01

    The phase-A design study of the Calibration Unit (CU) for the Multi-Unit Spectroscopic Explorer (MUSE) is presented. MUSE is an integral-field spectrograph for the 2nd generation of VLT instruments and offers a relative wide integral-field, adaptive-optics assisted spatial resolution, and a wavelength coverage between 465 and 930 nm. MUSE is a project of seven European institutes and is led by the Centre de Recherche Atronomique de Lyon (CRAL). Amongst other work-packages, the Astrophysical Institute Potsdam (AIP) is responsible for the Calibration Unit. The paper describes the calibration requirements, including issues related to spectral, image quality, and geometrical calibration. The opto-mechanical layout of the calibration unit is presented and the use of focal plane masks to evaluate image distortions and PSF degradations is explained.

  13. The ATLAS Electromagnetic Calorimeter Calibration Workshop

    CERN Multimedia

    Hong Ma; Isabelle Wingerter

    The ATLAS Electromagnetic Calorimeter Calibration Workshop took place at LAPP-Annecy from the 1st to the 3rd of October; 45 people attended the workshop. A detailed program was setup before the workshop. The agenda was organised around very focused presentations where questions were raised to allow arguments to be exchanged and answers to be proposed. The main topics were: Electronics calibration Handling of problematic channels Cluster level corrections for electrons and photons Absolute energy scale Streams for calibration samples Calibration constants processing Learning from commissioning Forty-five people attended the workshop. The workshop was on the whole lively and fruitful. Based on years of experience with test beam analysis and Monte Carlo simulation, and the recent operation of the detector in the commissioning, the methods to calibrate the electromagnetic calorimeter are well known. Some of the procedures are being exercised in the commisssioning, which have demonstrated the c...

  14. Variability of assay methods for total and free PSA after WHO standardization.

    Science.gov (United States)

    Foj, L; Filella, X; Alcover, J; Augé, J M; Escudero, J M; Molina, R

    2014-03-01

    The variability of total PSA (tPSA) and free PSA (fPSA) results among commercial assays has been suggested to be decreased by calibration to World Health Organization (WHO) reference materials. To characterize the current situation, it is necessary to know its impact in the critical cutoffs used in clinical practice. In the present study, we tested 167 samples with tPSA concentrations of 0 to 20 μg/L using seven PSA and six fPSA commercial assays, including Access, ARCHITECT i2000, ADVIA Centaur XP, IMMULITE 2000, Elecsys, and Lumipulse G1200, in which we only measured tPSA. tPSA and fPSA were measured in Access using the Hybritech and WHO calibrators. Passing-Bablok analysis was performed for PSA, and percentage of fPSA with the Hybritech-calibrated access comparison assay. For tPSA, relative differences were more than 10 % at 0.2 μg/L for ARCHITECT i2000, and at a critical concentration of 3, 4, and 10 μg/L, the relative difference was exceeded by ADVIA Centaur XP and WHO-calibrated Access. For percent fPSA, at a critical concentration of 10 %, the 10 % relative difference limit was exceeded by IMMULITE 2000 assay. At a critical concentration of 20 and 25 %, ADVIA Centaur XP, ARCHITECT i2000, and IMMULITE 2000 assays exceeded the 10 % relative difference limit. We have shown significant discordances between assays included in this study despite advances in standardization conducted in the last years. Further harmonization efforts are required in order to obtain a complete clinical concordance.

  15. MICROBIOLOGICAL ASSAY FOR VITAMIN B

    OpenAIRE

    Bishnoi Kapil*, , ,; Kataria Mahesh; Singhal Vipin; Gupta Deepika

    2012-01-01

    Micronutrients added to foods are analyzed using various procedures depending on their nature and properties. The microbiological assays are better than chemical method because any suitable change in vitamin molecule which may not be detected by chemical method will be revealed by change in microbial activity. The microbiological assay of vitamins is based upon the comparison of the stimulation of growth of bacteria by measured concentration of vitamin with that produced by known concentratio...

  16. A Cryogenic Infrared Calibration Target

    CERN Document Server

    Wollack, Edward J; Rinehart, Stephan A

    2014-01-01

    A compact cryogenic calibration target is presented that has a peak diffuse reflectance, $R \\le 0.003$, from $800-4,800\\,{\\rm cm}^{-1}$ $(12-2\\,\\mu$m). Upon expanding the spectral range under consideration to $400-10,000\\,{\\rm cm}^{-1}$ $(25-1\\,\\mu$m) the observed performance gracefully degrades to $R \\le 0.02$ at the band edges. In the implementation described, a high-thermal-conductivity metallic substrate is textured with a pyramidal tiling and subsequently coated with a thin lossy dielectric coating that enables high absorption and thermal uniformity across the target. The resulting target assembly is lightweight, has a low-geometric profile, and has survived repeated thermal cycling from room temperature to $\\sim4\\,$K. Basic design considerations, governing equations, and test data for realizing the structure described are provided. The optical properties of selected absorptive materials -- Acktar Fractal Black, Aeroglaze Z306, and Stycast 2850 FT epoxy loaded with stainless steel powder -- are character...

  17. Managing Workplace Diversity

    Directory of Open Access Journals (Sweden)

    Harold Andrew Patrick

    2012-04-01

    Full Text Available Diversity management is a process intended to create and maintain a positive work environment where the similarities and differences of individuals are valued. The literature on diversity management has mostly emphasized on organization culture; its impact on diversity openness; human resource management practices; institutional environments and organizational contexts to diversity-related pressures, expectations, requirements, and incentives; perceived practices and organizational outcomes related to managing employee diversity; and several other issues. The current study examines the potential barriers to workplace diversity and suggests strategies to enhance workplace diversity and inclusiveness. It is based on a survey of 300 IT employees. The study concludes that successfully managing diversity can lead to more committed, better satisfied, better performing employees and potentially better financial performance for an organization.

  18. Targets and assays for discovering novel antibacterial agents.

    Science.gov (United States)

    Donadio, Stefano; Carrano, Lucia; Brandi, Letizia; Serina, Stefania; Soffientini, Adolfo; Raimondi, Elena; Montanini, Nicoletta; Sosio, Margherita; Gualerzi, Claudio O

    2002-11-13

    The increasing frequency of nosocomial infections due to multi-resistant pathogens exerts a significant toll and calls for novel and better antibiotics. Different approaches can be used in the search for novel antibiotics acting on drug-resistant bacterial pathogens. We present some considerations on valid bacterial targets to be used for searching new antibiotics, and how the information from bacterial genome sequences can assist in choosing the appropriate targets. Other factors to be considered in target selection are the chemical diversity available for screening and its uniqueness. We will conclude discussing our strategy for searching novel antibacterials. This is based on a large collection of microbial extracts as a source of chemical diversity and on the use of specific targets essential for the viability of bacterial pathogens. Two assay strategies have been implemented: a pathway-based assay, where a series of essential bacterial targets is screened in a single assay; and a binding assay, where many targets can be screened individually in the same format.

  19. Intercomparison and calibration of dose calibrators used in nuclear medicine facilities

    CERN Document Server

    Costa, A M D

    2003-01-01

    The aim of this work was to establish a working standard for intercomparison and calibration of dose calibrators used in most of nuclear medicine facilities for the determination of the activity of radionuclides administered to patients in specific examinations or therapeutic procedures. A commercial dose calibrator, a set of standard radioactive sources, and syringes, vials and ampoules with radionuclide solutions used in nuclear medicine were utilized in this work. The commercial dose calibrator was calibrated for radionuclide solutions used in nuclear medicine. Simple instrument tests, such as linearity response and variation response with the source volume at a constant source activity concentration were performed. This instrument may be used as a reference system for intercomparison and calibration of other activity meters, as a method of quality control of dose calibrators utilized in nuclear medicine facilities.

  20. Beyond fossil calibrations: Realities of molecular clock practices in evolutionary biology

    Directory of Open Access Journals (Sweden)

    Christy Anna Hipsley

    2014-05-01

    Full Text Available Molecular-based divergence dating methods, or molecular clocks, are the primary neontological tool for estimating the temporal origins of clades. While the appropriate use of vertebrate fossils as external clock calibrations has stimulated heated discussions in the paleontological community, less attention has been given to the quality and implementation of other calibration types. In lieu of appropriate fossils, many studies rely on alternative sources of age constraints based on geological events, substitution rates and heterochronous sampling, as well as dates secondarily derived from previous analyses. To illustrate the breadth and frequency of calibration types currently employed, we conducted a literature survey of over 600 articles published from 2007 to 2013. Over half of all analyses implemented one or more fossil dates as constraints, followed by geological events and secondary calibrations (15% each. Vertebrate taxa were subjects of nearly half of all studies, while invertebrates and plants together accounted for 43%, followed by viruses, protists and fungi (3% each. Current patterns in calibration practices were disproportionate to the number of discussions on their proper use, particularly regarding plants and secondarily derived dates, which are both relatively neglected. Based on our survey, we provide a comprehensive overview of the latest approaches in clock calibration, and outline strengths and weaknesses associated with each. This critique should serve as a call to action for researchers across multiple communities, particularly those working on clades for which fossil records are poor, to develop their own guidelines regarding selection and implementation of alternative calibration types. This issue is particularly relevant now, as time-calibrated phylogenies are used for more than dating evolutionary origins, but often serve as the backbone of investigations into biogeography, diversity dynamics and rates of phenotypic

  1. Beyond fossil calibrations: realities of molecular clock practices in evolutionary biology.

    Science.gov (United States)

    Hipsley, Christy A; Müller, Johannes

    2014-01-01

    Molecular-based divergence dating methods, or molecular clocks, are the primary neontological tool for estimating the temporal origins of clades. While the appropriate use of vertebrate fossils as external clock calibrations has stimulated heated discussions in the paleontological community, less attention has been given to the quality and implementation of other calibration types. In lieu of appropriate fossils, many studies rely on alternative sources of age constraints based on geological events, substitution rates and heterochronous sampling, as well as dates secondarily derived from previous analyses. To illustrate the breadth and frequency of calibration types currently employed, we conducted a literature survey of over 600 articles published from 2007 to 2013. Over half of all analyses implemented one or more fossil dates as constraints, followed by geological events and secondary calibrations (15% each). Vertebrate taxa were subjects in nearly half of all studies, while invertebrates and plants together accounted for 43%, followed by viruses, protists and fungi (3% each). Current patterns in calibration practices were disproportionate to the number of discussions on their proper use, particularly regarding plants and secondarily derived dates, which are both relatively neglected in methodological evaluations. Based on our survey, we provide a comprehensive overview of the latest approaches in clock calibration, and outline strengths and weaknesses associated with each. This critique should serve as a call to action for researchers across multiple communities, particularly those working on clades for which fossil records are poor, to develop their own guidelines regarding selection and implementation of alternative calibration types. This issue is particularly relevant now, as time-calibrated phylogenies are used for more than dating evolutionary origins, but often serve as the backbone of investigations into biogeography, diversity dynamics and rates of

  2. International diversity management

    DEFF Research Database (Denmark)

    Lauring, Jakob

    2013-01-01

    While the concern with demographic diversity in organizations has increased during recent years, international diversity management still remains an understudied area. This is unfortunate since the transfer of diversity management practices within multinational corporations faces particular...... challenges in balancing between global integration and local responsiveness. The aim of this paper is to illustrate some of the central problems that multinational corporations need to deal with when transferring diversity management practices from headquarters to local subsidiaries. This is illustrated...

  3. Correlation between the genotoxicity endpoints measured by two different genotoxicity assays: comet assay and CBMN assay

    Directory of Open Access Journals (Sweden)

    Carina Ladeira

    2015-06-01

    The results concerning of positive findings by micronuclei and non significant ones by comet assay, are corroborated by Deng et al. (2005 study performed in workers occupationally exposed to methotrexate, also a cytostatic drug. According to Cavallo et al. (2009, the comet assay seems to be more suitable for the prompt evaluation of the genotoxic effects, for instance, of polycyclic aromatic hydrocarbons mixtures containing volatile substances, whereas the micronucleus test seems more appropriate to evaluate the effects of exposure to antineoplastic agents. However, there are studies that observed an increase in both the comet assay and the micronucleus test in nurses handling antineoplastic drugs, although statistical significance was only seen in the comet assay, quite the opposite of our results (Maluf & Erdtmann, 2000; Laffon et al. 2005.

  4. Unity in Diversity.

    Science.gov (United States)

    Purves, Alan C.

    The cultural diversities of peoples and dialects in the United States have brought a richness to the English language that has made it one of the most supple of all the languages in the world. In addition to the diversity in the language are the diversities in literature, technology, nationality, politics, and styles of teaching. Teachers of…

  5. Diversity by design

    NARCIS (Netherlands)

    Helberger, N.

    2011-01-01

    How do you get citizens/media consumers to voluntarily choose to expose themselves to diverse content? Is there a role for government in helping people make diverse choices? Professor Helberger addresses these questions by suggesting "diversity by design" as an antidote to the ironic fact that broad

  6. The State of Diversity.

    Science.gov (United States)

    Josey, E. J.

    1994-01-01

    Examines what is being done to implement cultural diversity in libraries. Topics addressed include affirmative action; defining cultural diversity, including the significance of ethnicity, race, and race relations in the workplace; problems in implementing cultural diversity; and examples of successful implementation programs. (Contains three…

  7. Multilevel and Diverse Classrooms

    Science.gov (United States)

    Baurain, Bradley, Ed.; Ha, Phan Le, Ed.

    2010-01-01

    The benefits and advantages of classroom practices incorporating unity-in-diversity and diversity-in-unity are what "Multilevel and Diverse Classrooms" is all about. Multilevel classrooms--also known as mixed-ability or heterogeneous classrooms--are a fact of life in ESOL programs around the world. These classrooms are often not only multilevel…

  8. Calibrating page sized Gafchromic EBT3 films

    Energy Technology Data Exchange (ETDEWEB)

    Crijns, W.; Maes, F.; Heide, U. A. van der; Van den Heuvel, F. [Department of Radiation Oncology, University Hospitals Leuven, Herestraat 49, 3000 Leuven (Belgium); Department ESAT/PSI-Medical Image Computing, Medical Imaging Research Center, KU Leuven, Herestraat 49, 3000 Leuven (Belgium); Department of Radiation Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands); Department of Radiation Oncology, University Hospitals Leuven, Herestraat 49, 3000 Leuven (Belgium)

    2013-01-15

    Purpose: The purpose is the development of a novel calibration method for dosimetry with Gafchromic EBT3 films. The method should be applicable for pretreatment verification of volumetric modulated arc, and intensity modulated radiotherapy. Because the exposed area on film can be large for such treatments, lateral scan errors must be taken into account. The correction for the lateral scan effect is obtained from the calibration data itself. Methods: In this work, the film measurements were modeled using their relative scan values (Transmittance, T). Inside the transmittance domain a linear combination and a parabolic lateral scan correction described the observed transmittance values. The linear combination model, combined a monomer transmittance state (T{sub 0}) and a polymer transmittance state (T{sub {infinity}}) of the film. The dose domain was associated with the observed effects in the transmittance domain through a rational calibration function. On the calibration film only simple static fields were applied and page sized films were used for calibration and measurements (treatment verification). Four different calibration setups were considered and compared with respect to dose estimation accuracy. The first (I) used a calibration table from 32 regions of interest (ROIs) spread on 4 calibration films, the second (II) used 16 ROIs spread on 2 calibration films, the third (III), and fourth (IV) used 8 ROIs spread on a single calibration film. The calibration tables of the setups I, II, and IV contained eight dose levels delivered to different positions on the films, while for setup III only four dose levels were applied. Validation was performed by irradiating film strips with known doses at two different time points over the course of a week. Accuracy of the dose response and the lateral effect correction was estimated using the dose difference and the root mean squared error (RMSE), respectively. Results: A calibration based on two films was the optimal

  9. Increased Automation in Stereo Camera Calibration Techniques

    Directory of Open Access Journals (Sweden)

    Brandi House

    2006-08-01

    Full Text Available Robotic vision has become a very popular field in recent years due to the numerous promising applications it may enhance. However, errors within the cameras and in their perception of their environment can cause applications in robotics to fail. To help correct these internal and external imperfections, stereo camera calibrations are performed. There are currently many accurate methods of camera calibration available; however, most or all of them are time consuming and labor intensive. This research seeks to automate the most labor intensive aspects of a popular calibration technique developed by Jean-Yves Bouguet. His process requires manual selection of the extreme corners of a checkerboard pattern. The modified process uses embedded LEDs in the checkerboard pattern to act as active fiducials. Images are captured of the checkerboard with the LEDs on and off in rapid succession. The difference of the two images automatically highlights the location of the four extreme corners, and these corner locations take the place of the manual selections. With this modification to the calibration routine, upwards of eighty mouse clicks are eliminated per stereo calibration. Preliminary test results indicate that accuracy is not substantially affected by the modified procedure. Improved automation to camera calibration procedures may finally penetrate the barriers to the use of calibration in practice.

  10. Calibrators and control samples for bilirubinometers.

    Science.gov (United States)

    Blijenberg, B G; Brügmann, G; Geilenkeuser, W J; Kusyschyn, R; Röhle, G; Schlebusch, H; Schneider, C

    1993-06-01

    The different matrix properties of neonatal serum and commercial control samples can lead to considerable errors in the calibration and control of bilirubinometers. These difficulties can be avoided by calibration with serum from healthy adults which is supplemented with unconjugated bilirubin. But this procedure is impracticable for most routine laboratories. Under certain preconditions, control samples, with bilirubin concentrations determined with correctly calibrated bilirubinometers or spectrophotometers, are also suitable as calibrators. This was established by determination of the bilirubin concentration of 16 different control samples, using both the reference method and correctly calibrated bilirubinometers or spectrophotometers in three or four specialist laboratories. This was also confirmed in several interlaboratory surveys, some involving up to 72 laboratories. The results of these investigations show that a control sample should be used for the calibration of a bilirubinometer only if it meets the following preconditions: 1. There should be no significant difference between the bilirubin values determined with the reference method and with a correctly calibrated spectrophotometer or bilirubinometer. 2. The bilirubin concentration should lie in the range 230-300 mumol/l. The photometric response of bilirubinometers has a limited linear range, so that analytical results greater than 300 mumol/l must be rated as basically unreliable.

  11. Landsat-7 ETM+ radiometric calibration status

    Science.gov (United States)

    Barsi, Julia A.; Markham, Brian L.; Czapla-Myers, Jeffrey S.; Helder, Dennis L.; Hook, Simon J.; Schott, John R.; Haque, Md. Obaidul

    2016-09-01

    Now in its 17th year of operation, the Enhanced Thematic Mapper + (ETM+), on board the Landsat-7 satellite, continues to systematically acquire imagery of the Earth to add to the 40+ year archive of Landsat data. Characterization of the ETM+ on-orbit radiometric performance has been on-going since its launch in 1999. The radiometric calibration of the reflective bands is still monitored using on-board calibration devices, though the Pseudo-Invariant Calibration Sites (PICS) method has proven to be an effective tool as well. The calibration gains were updated in April 2013 based primarily on PICS results, which corrected for a change of as much as -0.2%/year degradation in the worst case bands. A new comparison with the SADE database of PICS results indicates no additional degradation in the updated calibration. PICS data are still being tracked though the recent trends are not well understood. The thermal band calibration was updated last in October 2013 based on a continued calibration effort by NASA/Jet Propulsion Lab and Rochester Institute of Technology. The update accounted for a 0.036 W/m2 sr μm or 0.26K at 300K bias error. The updated lifetime trend is now stable to within +/- 0.4K.

  12. Preliminary evaluation of a Neutron Calibration Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Alvarenga, Talysson S.; Neves, Lucio P.; Perini, Ana P.; Sanches, Matias P.; Mitake, Malvina B.; Caldas, Linda V.E., E-mail: talvarenga@ipen.br, E-mail: lpneves@ipen.br, E-mail: aperini@ipen.br, E-mail: msanches@ipen.br, E-mail: mbmitake@ipen.br, E-mail: lcaldas@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Federico, Claudio A., E-mail: claudiofederico@ieav.cta.br [Instituto de Estudos Avancados (IEAv/DCTA), Sao Jose dos Campos, SP (Brazil). Dept. de Ciencia e Tecnologia Aeroespacial

    2013-07-01

    In the past few years, Brazil and several other countries in Latin America have experimented a great demand for the calibration of neutron detectors, mainly due to the increase in oil prospection and extraction. The only laboratory for calibration of neutron detectors in Brazil is localized at the Institute for Radioprotection and Dosimetry (IRD/CNEN), Rio de Janeiro, which is part of the IAEA SSDL network. This laboratory is the national standard laboratory in Brazil. With the increase in the demand for the calibration of neutron detectors, there is a need for another calibration services. In this context, the Calibration Laboratory of IPEN/CNEN, Sao Paulo, which already offers calibration services of radiation detectors with standard X, gamma, beta and alpha beams, has recently projected a new calibration laboratory for neutron detectors. In this work, the ambient equivalent dose rate (H⁎(10)) was evaluated in several positions inside and around this laboratory, using Monte Carlo simulation (MCNP5 code), in order to verify the adequateness of the shielding. The obtained results showed that the shielding is effective, and that this is a low-cost methodology to improve the safety of the workers and evaluate the total staff workload. (author)

  13. Dry calibration of ultrasonic gas flow meters

    Energy Technology Data Exchange (ETDEWEB)

    De Boer, G.; Lansing, J.

    1997-07-01

    At present in most European countries it is customary that turbine meters, or the newer ultrasonic gas flow meters, when used in fiscal metering or custody transfer metering applications, are calibrated in a test facility by comparison to standards or reference devices. For reason of practical and operational drawbacks, costs involved and availability of only a limited number of calibration facilities, another way of meter verification is advantageous. For orifice metering the practice of dry calibration is well established; that is, meter verification is based upon examination of the geometry and installation of the orifice plate and a function check of the read out devices. Although for turbine meters a flow (wet) calibration may be a necessity, it will be shown that ultrasonic gas flow meters can be dry calibrated in the same way as orifice meters. As a basis for the acceptance of a dry calibration procedure for ultrasonic gas flow meters, a sensitivity analysis of the relevant variables with respect to the meter's accuracy is presented. Further test results are presented that demonstrate the feasibility of the concept of dry calibration applied to ultrasonic gas flow meters. (author)

  14. Calibration of the COBE FIRAS instrument

    Science.gov (United States)

    Fixsen, D. J.; Cheng, E. S.; Cottingham, D. A.; Eplee, R. E., Jr.; Hewagama, T.; Isaacman, R. B.; Jensen, K. A.; Mather, J. C.; Massa, D. L.; Meyer, S. S.

    1994-01-01

    The Far-Infrared Absolute Spectrophotometer (FIRAS) instrument on the Cosmic Background Explorer (COBE) satellite was designed to accurately measure the spectrum of the cosmic microwave background radiation (CMBR) in the frequency range 1-95/cm with an angular resolution of 7 deg. We describe the calibration of this instrument, including the method of obtaining calibration data, reduction of data, the instrument model, fitting the model to the calibration data, and application of the resulting model solution to sky observations. The instrument model fits well for calibration data that resemble sky condition. The method of propagating detector noise through the calibration process to yield a covariance matrix of the calibrated sky data is described. The final uncertainties are variable both in frequency and position, but for a typical calibrated sky 2.6 deg square pixel and 0.7/cm spectral element the random detector noise limit is of order of a few times 10(exp -7) ergs/sq cm/s/sr cm for 2-20/cm, and the difference between the sky and the best-fit cosmic blackbody can be measured with a gain uncertainty of less than 3%.

  15. Vicarious Calibration of Beijing-1 Multispectral Imagers

    Directory of Open Access Journals (Sweden)

    Zhengchao Chen

    2014-02-01

    Full Text Available For on-orbit calibration of the Beijing-1 multispectral imagers (Beijing-1/MS, a field calibration campaign was performed at the Dunhuang calibration site during September and October of 2008. Based on the in situ data and images from Beijing-1 and Terra/Moderate Resolution Imaging Spectroradiometer (MODIS, three vicarious calibration methods (i.e., reflectance-based, irradiance-based, and cross-calibration were used to calculate the top-of-atmosphere (TOA radiance of Beijing-1. An analysis was then performed to determine or identify systematic and accidental errors, and the overall uncertainty was assessed for each individual method. The findings show that the reflectance-based method has an uncertainty of more than 10% if the aerosol optical depth (AOD exceeds 0.2. The cross-calibration method is able to reach an error level within 7% if the images are selected carefully. The final calibration coefficients were derived from the irradiance-based data for 6 September 2008, with an uncertainty estimated to be less than 5%.

  16. Landsat TM and ETM+ thermal band calibration

    Science.gov (United States)

    Barsi, J.A.; Schott, J.R.; Palluconi, F. D.; Helder, D.L.; Hook, S.J.; Markham, B.L.; Chander, G.; O'Donnell, E. M.

    2003-01-01

    Landsat-5 has been imaging the Earth since March 1984, and Landsat-7 was added to the series of Landsat instruments in April 1999. The Landsat Project Science Office and the Landsat-7 Image Assessment System have been monitoring the on-board calibration of Landsat-7 since launch. Additionally, two separate university teams have been evaluating the on-board thermal calibration of Landsat-7 through ground-based measurements since launch. Although not monitored as closely over its lifetime, a new effort is currently being made to validate the calibration of Landsat-5. Two university teams are beginning to collect ground truth under Landsat-5, along with using other vicarious calibration methods to go back into the archive to validate the history of the calibration of Landsat-5. This paper considers the calibration efforts for the thermal band, band 6, of both the Landsat-5 and Landsat-7 instruments. Though stable since launch, Landsat-7 had an initial calibration error of about 3 K, and changes were made to correct for this beginning 1 October 2000 for data processed with the National Landsat Archive Production System (NLAPS) and beginning 20 December 2000 for data processed with the Landsat Product Generation System (LPGS). Recent results from Landsat-5 vicarious calibration efforts show an offset of –0.7 K over the lifetime of the instrument. This suggests that historical calibration efforts may have been detecting errors in processing systems rather than changes in the instrument. A correction to the Landsat-5 processing has not yet been implemented but will be in the near future.

  17. Commutability of the CRM 470 C-reactive protein value in the Dade Behring N High Sensitivity CRP assay.

    Science.gov (United States)

    Johnson, A Myron; Ledue, Thomas B; Collins, Marilyn F

    2003-02-01

    Certified Reference Material 470 (CRM 470) demonstrates commutability with both the manufacturer's calibrator and with dilutions of serum pools in the Dade Behring N High Sensitivity assay for C-reactive protein (CRP). Both regression and back calibration show similar nonlinearity for all materials, largely due to the method of calibration curve fitting used in this assay. Significant differences in values among the currently available commercial assays can be largely overcome by using appropriate calibration curve fitting and the recommended value transfer protocol, which includes a minimum of two assay runs on each of at least 3 separate days, with weight correction of all reconstitutions and dilutions. An initial weight-corrected dilution should be made each day because of the relatively high level of CRP in CRM 470. In our opinion, the degree of nonlinearity, imprecision, and differences in values in currently available assays renders the use of fixed clinical decision cut-points questionable for high-sensitivity CRP. An alternative approach is suggested.

  18. Automated system for the calibration of magnetometers

    DEFF Research Database (Denmark)

    Petrucha, Vojtech; Kaspar, Petr; Ripka, Pavel

    2009-01-01

    A completely nonmagnetic calibration platform has been developed and constructed at DTU Space (Technical University of Denmark). It is intended for on-site scalar calibration of high-precise fluxgate magnetometers. An enhanced version of the same platform is being built at the Czech Technical Uni...... through custom-made optical incremental sensors. The system is controlled by a microcontroller, which executes commands from a computer. The properties of the system as well as calibration and measurement results will be presented. ©2009 American Institute of Physics...

  19. New method for spectrofluorometer monochromator wavelength calibration.

    Science.gov (United States)

    Paladini, A A; Erijman, L

    1988-09-01

    A method is presented for wavelength calibration of spectrofluorometer monochromators. It is based on the distortion that the characteristic absorption bands of glass filters (holmium or didymium oxide), commonly used for calibration of spectrophotometers, introduce in the emitted fluorescence of fluorophores like indole, diphenyl hexatriene, xylene or rhodamine 6G. Those filters or a well characterized absorber with sharp bands like benzene vapor can be used for the same purpose. The wavelength calibration accuracy obtained with this method is better than 0.1 nm, and requires no modification in the geometry of the spectrofluorometer sample compartment.

  20. 1% calibration errors in MQY magnets

    CERN Document Server

    Bach, T; Langner, A; Levinsen, Y; McAteer, M; Maclean, E H; Persson, T; Skowronski, P; Tomás, R; Todesco, E; White, S

    2013-01-01

    Errors in the range of 1% have been observed for the MQY magnets in beam-based measurements. Furthermore, inconsistencies have been observed when comparing previous magnetic measurements to the LHC LSA database. After a revision, new calibration data have been extracted and were compared to the optics corrections that have been obtained from beam-based measurements. In 27-11-2012 a MD session has been performed to test these calibration data. This paper reports on the experimental verification of the new calibration data for the MQY quadrupole magnets.

  1. Calibration for 3D Structured Light Measurement

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A calibration procedure was developed for three-dimensional(3D) binocular structured light measurement systems. In virtue of a specially designed pattern, matching points in stereo images are extracted. And then sufficient 3D space points are obtained through pairs of images with the intrinsic and extrinsic parameters of each camera estimated prior and consequently some lights are calibrated by means of multi point fitting. Finally, a mathematical model is applied to interpolate and approximate all dynamic scanning lights based on geometry. The process of calibration method is successfully used in the binocular 3D measurement system based on structured lights and the 3D reconstruction results are satisfying.

  2. Calibration of Ground-based Lidar instrument

    DEFF Research Database (Denmark)

    Yordanova, Ginka; Gómez Arranz, Paula

    This report presents the result of the lidar calibration performed for the given Ground-based Lidar at DTU’s test site for large wind turbines at Høvsøre, Denmark. Calibration is here understood as the establishment of a relation between the reference wind speed measurements with measurement...... uncertainties provided by measurement standard and corresponding lidar wind speed indications with associated measurement uncertainties. The lidar calibration concerns the 10 minute mean wind speed measurements. The comparison of the lidar measurements of the wind direction with that from wind vanes...

  3. Calibration of Ground -based Lidar instrument

    DEFF Research Database (Denmark)

    Villanueva, Héctor; Yordanova, Ginka

    This report presents the result of the lidar calibration performed for the given Ground-based Lidar at DTU’s test site for large wind turbines at Høvsøre, Denmark. Calibration is here understood as the establishment of a relation between the reference wind speed measurements with measurement...... uncertainties provided by measurement standard and corresponding lidar wind speed indications with associated measurement uncertainties. The lidar calibration concerns the 10 minute mean wind speed measurements. The comparison of the lidar measurements of the wind direction with that from wind vanes...

  4. Single Camera Calibration in 3D Vision

    Directory of Open Access Journals (Sweden)

    Caius SULIMAN

    2009-12-01

    Full Text Available Camera calibration is a necessary step in 3D vision in order to extract metric information from 2D images. A camera is considered to be calibrated when the parameters of the camera are known (i.e. principal distance, lens distorsion, focal length etc.. In this paper we deal with a single camera calibration method and with the help of this method we try to find the intrinsic and extrinsic camera parameters. The method was implemented with succes in the programming and simulation environment Matlab.

  5. The Calibration Stategy of CMS Electromagnetic Calorimeter

    CERN Document Server

    Meridiani, P

    2004-01-01

    Calibration is one of the main factors that set limits on the ultimate performance of the CMS electromagnetic calorimeter (ECAL) at LHC. Crystals raw intercalibration from laboratory measurements during assembly will be available for all the crystals and has been demonstrated to be a good precalibration value at the start-up; some crystals will be also intercalibrated using an electron beam. In situ calibration with physics events will be the main tool to reduce the constant term of the emergy resolution to the design goal of 0.5%. In the following the calibration strategy will be described in detail.

  6. Diversity Management: Seeking Validation

    Directory of Open Access Journals (Sweden)

    M. Tony Bledsoe

    2011-01-01

    Full Text Available Diversity management is widely valued in higher education today, but closer examination often reveals a lack of action to support the level of diversity that institutions claim to embrace in many of their strategic documents. This paper includes an assessment of diversity management within South Carolina’s technical colleges and an examination of survey results.  It is a companion study to a prior study of diversity in North Carolina Independent Colleges and Universities (NCICU.  The purpose of that research was to review campus-wide documents and structure of schools in the NCICU to determine diversity transparency (Bledsoe/Oatsvall.

  7. 40 CFR 1065.340 - Diluted exhaust flow (CVS) calibration.

    Science.gov (United States)

    2010-07-01

    ... the flow meter has been calibrated with such a restriction. (e) PDP calibration. Calibrate a positive-displacement pump (PDP) to determine a flow-versus-PDP speed equation that accounts for flow leakage...

  8. Calibration report for Avent 5-beam Demonstrator lidar

    DEFF Research Database (Denmark)

    Borraccino, Antoine; Courtney, Michael

    . Their estimation is the ultimate goal of a calibration: a relation is established between reference measurements from calibrated instruments and corresponding LiDAR indications. Traceability in the calibration is obtained by transferring measurement uncertainties from the reference instrument through...

  9. Calibration of routine dosimeters in radiation processing: Validation procedure for in-plant calibration

    Directory of Open Access Journals (Sweden)

    Šećerov Bojana Lj.

    2011-01-01

    Full Text Available The essential prerequisite of radiation dosimetry is to provide quality assurance and documentation that the irradiation procedure has been carried out according to the specification requirement of correct calibration of the chosen dosimetry system. At the Radiation Plant of the Vinča Institute of Nuclear Sciences we compared two recommended protocols of irradiation procedures in the calibration of dosimetry systems in radiation processing: (1 by irradiation of routine dosimeters (ethanol-chlorobenzene - ECB at the calibration laboratory and (2, by in-plant calibration with alanine transfer - dosimeters. The critical point for in-plant calibration is irradiation geometry, so we carefully positioned the phantom carrying both dosimeters in order to minimize dose gradients across the sample. The analysis of results obtained showed that the difference among determined absorbed doses for the construction of calibration curves between these two methods, (alanine vs. ECB, is less than 1%. The difference in combined standard uncertainty for each calibration procedure is 0.1%. These results demonstrate that our in-plant calibration is as good as calibration by irradiation at the calibration laboratory and validates our placement of the irradiation phantom during irradiation.

  10. Calibration methods for rotating shadowband irradiometers and evaluation of calibration duration

    Science.gov (United States)

    Jessen, W.; Wilbert, S.; Nouri, B.; Geuder, N.; Fritz, H.

    2015-10-01

    Resource assessment for Concentrated Solar Power (CSP) needs accurate Direct Normal Irradiance (DNI) measurements. An option for such measurement campaigns are Rotating Shadowband Irradiometers (RSIs) with a thorough calibration. Calibration of RSIs and Si-sensors in general is complex because of the inhomogeneous spectral response of such sensors and incorporates the use of several correction functions. A calibration for a given atmospheric condition and air mass might not work well for a different condition. This paper covers procedures and requirements for two calibration methods for the calibration of Rotating Shadowband Irradiometers. The necessary duration of acquisition of test measurements is examined in regard to the site specific conditions at Plataforma Solar de Almeria (PSA) in Spain. Data sets of several long-term calibration periods from PSA are used to evaluate the deviation of results from calibrations with varying duration from the long-term result. The findings show that seasonal changes of environmental conditions are causing small but noticeable fluctuation of calibration results. Certain periods (i.e. November to January and April to May) show a higher likelihood of particularly adverse calibration results. These effects can partially be compensated by increasing the inclusions of measurements from outside these periods. Consequently, the duration of calibrations at PSA can now be selected depending on the time of the year in which measurements are commenced.

  11. Calibration methods for rotating shadowband irradiometers and evaluation of calibration duration

    Directory of Open Access Journals (Sweden)

    W. Jessen

    2015-10-01

    Full Text Available Resource assessment for Concentrated Solar Power (CSP needs accurate Direct Normal Irradiance (DNI measurements. An option for such measurement campaigns are Rotating Shadowband Irradiometers (RSIs with a thorough calibration. Calibration of RSIs and Si-sensors in general is complex because of the inhomogeneous spectral response of such sensors and incorporates the use of several correction functions. A calibration for a given atmospheric condition and air mass might not work well for a different condition. This paper covers procedures and requirements for two calibration methods for the calibration of Rotating Shadowband Irradiometers. The necessary duration of acquisition of test measurements is examined in regard to the site specific conditions at Plataforma Solar de Almeria (PSA in Spain. Data sets of several long-term calibration periods from PSA are used to evaluate the deviation of results from calibrations with varying duration from the long-term result. The findings show that seasonal changes of environmental conditions are causing small but noticeable fluctuation of calibration results. Certain periods (i.e. November to January and April to May show a higher likelihood of particularly adverse calibration results. These effects can partially be compensated by increasing the inclusions of measurements from outside these periods. Consequently, the duration of calibrations at PSA can now be selected depending on the time of the year in which measurements are commenced.

  12. Forecast of physicochemical properties and chemical composition of gasoline from infrared spectra, using multivariate calibration; Previsao de propriedades fisico-quimicas e composicao quimica da gasolina a partir de espectros infravermelhos, utilizando calibracao multivariada

    Energy Technology Data Exchange (ETDEWEB)

    Cocco, Lilian Cristina; Yamamoto, Carlos Itsuo [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Lab. de Analise de Combustiveis Automotivos (LACAUTets)

    2008-07-01

    This work describes the attainment of mathematical models, applying multivariate calibration in infrared spectrum with ATR, from 128 gasoline samples with diverse chemical compositions, collected in a period of two and a half years. Infrared spectra had been used to assemble the input matrix for the modeling, whereas the standardized assays and gaseous chromatography had supplied the output matrices. Ninety samples were been used for training and 38 for testing. In order to calibrate chemical composition from chromatography, the techniques of mass spectrometry and chemical ionization were used to identify unknown substances and improve the fitting of the mathematical models. Two hundred and ninety substances were detected and identified, from which 100 were unknown. Six PLS/PCR models were attained to predict some properties as specific mass, Reid vapor pressure, T10, T50, T90 and PFE from distillation curve. Another six PLS/PCR models were attained to predict the amount of aromatics, paraffins, isoparaffins, naphthenes, olefins and oxygenates. In general, mathematical models were attained with good training fit, with correlation coefficients higher than 0,975 (T10) and reaching a maximum of 0,998 (naphthenes) and they are able to forecast an average chemical percentage and properties of interest from gasoline, with acceptable prediction errors. (author)

  13. Barcoded microchips for biomolecular assays.

    Science.gov (United States)

    Zhang, Yi; Sun, Jiashu; Zou, Yu; Chen, Wenwen; Zhang, Wei; Xi, Jianzhong Jeff; Jiang, Xingyu

    2015-01-20

    Multiplexed assay of analytes is of great importance for clinical diagnostics and other analytical applications. Barcode-based bioassays with the ability to encode and decode may realize this goal in a straightforward and consistent manner. We present here a microfluidic barcoded chip containing several sets of microchannels with different widths, imitating the commonly used barcode. A single barcoded microchip can carry out tens of individual protein/nucleic acid assays (encode) and immediately yield all assay results by a portable barcode reader or a smartphone (decode). The applicability of a barcoded microchip is demonstrated by human immunodeficiency virus (HIV) immunoassays for simultaneous detection of three targets (anti-gp41 antibody, anti-gp120 antibody, and anti-gp36 antibody) from six human serum samples. We can also determine seven pathogen-specific oligonucleotides by a single chip containing both positive and negative controls.

  14. Radioreceptor assay method for insulin

    Energy Technology Data Exchange (ETDEWEB)

    Mori, K.F.; Wood, R.J. (Bureau of Drug Research, Health and Welfare Canada, Ottawa, Ontario. Health Protection Branch)

    1984-01-01

    A sensitive practical radioreceptor assay method for pharmaceutical insulin products has been developed with partially purified rat liver plasma membranes and the optimal conditions under which the best overall assay performance is obtainable have been defined. Intra- and inter-assay variations of the method averaged 7.3 and 12.2% of the man, respectively, when expressed as the coefficient of variation. Potency estimates of an insulin product obtained with the proposed method correlated well with those determined by the mouse convulsion bioassay method. Liver membranes prepared according to the method could be stored for up to ten weeks at 4/sup 0/C and for 6 months or more at -18/sup 0/C without losing insulin-binding ability.

  15. Linking Diversity and Differentiation

    Directory of Open Access Journals (Sweden)

    Hans-Rolf Gregorius

    2010-03-01

    Full Text Available Generally speaking, the term differentiation refers to differences between collections for the distribution of specified traits of their members, while diversity deals with (effective numbers of trait states (types. Counting numbers of types implies discrete traits such as alleles and genotypes in population genetics or species and taxa in ecology. Comparisons between the concepts of differentiation and diversity therefore primarily refer to discrete traits. Diversity is related to differentiation through the idea that the total diversity of a subdivided collection should be composed of the diversity within the subcollections and a complement called “diversity between subcollections”. The idea goes back to the perception that the mixing of differentiated collections increases diversity. Several existing concepts of “diversity between subcollections” are based on this idea. Among them, β-diversity and fixation (inadvertently called differentiation are the most prominent in ecology and in population genetics, respectively. The pertaining measures are shown to quantify the effect of differentiation in terms of diversity components, though from a dual perspective: the classical perspective of differentiation between collections for their type compositions, and the reverse perspective of differentiation between types for their collection affiliations. A series of measures of diversity-oriented differentiation is presented that consider this dual perspective at two levels of diversity partitioning: the overall type or subcollection diversity and the joint type-subcollection diversity. It turns out that, in contrast with common notions, the measures of fixation (such as FST or GST refer to the perspective of type rather than subcollection differentiation. This unexpected observation strongly suggests that the popular interpretations of fixation measures must be reconsidered.

  16. ARM Shortwave and Longwave Radiometer Calibrations

    Energy Technology Data Exchange (ETDEWEB)

    Dooraghi, Mike; Kutchenreiter, Mark; Reda, Ibrahim; Habte, Aron; Sengupta, Manajit; Andreas, Afshin; Newman, Martina; Webb, Craig

    2017-03-23

    This presentation provides a high-level overview of shortwave and longwave calibrations performed at the U.S. Department of Energy's Atmospheric Radiation Measurement program Southern Great Plains site.

  17. Calibration beads containing luminescent lanthanide ion complexes

    Science.gov (United States)

    The reliability of lanthanide luminescence measurements, by both flow cytometry and digital microscopy, will be enhanced by the availability of narrow-band emitting lanthanide calibration beads. These beads can also be used to characterize spectrographic instruments, including mi...

  18. Calibration of the JEM-EUSO detector

    Directory of Open Access Journals (Sweden)

    Gorodetzky P.

    2013-06-01

    Full Text Available In order to unveil the mystery of ultra high energy cosmic rays (UHECRs, JEM-EUSO (Extreme Universe Space Observatory on-board Japan Experiment Module will observe extensive air showers induced by UHECRs from the International Space Station orbit with a huge acceptance. Calibration of the JEM-EUSO instrument, which consists of Fresnel optics and a focal surface detector with 5000 photomultipliers, is very important to discuss the origin of UHECRs precisely with the observed results. In this paper, the calibration before launch and on-orbit is described. The calibration before flight will be performed as precisely as possible with integrating spheres. In the orbit, the relative change of the performance will be checked regularly with on-board and on-ground light sources. The absolute calibration of photon detection efficiency may be performed with the moon, which is a stable light source in the nature.

  19. Calibration of a photomultiplier array spectrometer

    Science.gov (United States)

    Bailey, Steven A.; Wright, C. Wayne; Piazza, Charles R.

    1989-01-01

    A systematic approach to the calibration of a photomultiplier array spectrometer is presented. Through this approach, incident light radiance derivation is made by recognizing and tracing gain characteristics for each photomultiplier tube.

  20. Computer Vision Assisted Virtual Reality Calibration

    Science.gov (United States)

    Kim, W.

    1999-01-01

    A computer vision assisted semi-automatic virtual reality (VR) calibration technology has been developed that can accurately match a virtual environment of graphically simulated three-dimensional (3-D) models to the video images of the real task environment.

  1. Calibration of pressure gauge for Cherenkov detector

    CERN Document Server

    Saponjic, Nevena

    2013-01-01

    Solartron/Hamilton pressure gauges are used to monitor the gas pressure in the particle beam detectors installed in the experimental areas. Here is description of the test bench for the calibration of these gauges in Labview.

  2. Calibration and verification of environmental models

    Science.gov (United States)

    Lee, S. S.; Sengupta, S.; Weinberg, N.; Hiser, H.

    1976-01-01

    The problems of calibration and verification of mesoscale models used for investigating power plant discharges are considered. The value of remote sensors for data acquisition is discussed as well as an investigation of Biscayne Bay in southern Florida.

  3. A transmission calibration method for superconducting resonators

    CERN Document Server

    Cataldo, Giuseppe; Barrentine, Emily M; Brown, Ari D; Moseley, Samuel H; U-Yen, Kongpop

    2014-01-01

    A method is proposed and experimentally explored for \\textit{in-situ} calibration of complex transmission data for superconducting microwave resonators. This cryogenic calibration method accounts for the instrumental transmission response between the vector network analyzer reference plane and the device calibration plane. Once calibrated, the observed resonator response was modeled in detail by two approaches. The first, a phenomenological model based on physically realizable rational functions, enables the extraction of multiple resonance frequencies and widths for coupled resonators without explicit specification of the circuit network. In the second, an ABCD-matrix representation for the distributed transmission line circuit is used to model the observed response from the characteristic impedance and propagation constant. When used in conjunction with electromagnetic simulations, the kinetic inductance fraction can be determined with this method with an accuracy of 2%. Datasets for superconducting microst...

  4. Low Power, Self Calibrated Vector Magnetometer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase I SBIR project investigates a novel approach to vector magnetometry based on high precision measurements of the total magnetic field. The calibration is...

  5. Terminology of ranging measurements and DSS calibrations

    Science.gov (United States)

    Komarek, T. A.; Otoshi, T. Y.

    1976-01-01

    A set of basic terminology related to deep space ranging measurements is proposed. Calibration equations are derived for the dish-mounted zero delay device method for 26-m antenna systems and the translator method for 64-m antenna systems.

  6. HPS instrument calibration laboratory accreditation program

    Energy Technology Data Exchange (ETDEWEB)

    Masse, F.X; Eisenhower, E.H.; Swinth, K.L.

    1993-12-31

    The purpose of this paper is to provide an accurate overview of the development and structure of the program established by the Health Physics Society (HPS) for accrediting instrument calibration laboratories relative to their ability to accurately calibrate portable health physics instrumentation. The purpose of the program is to provide radiation protection professionals more meaningful direct and indirect access to the National Institute of Standards and Technology (NIST) national standards, thus introducing a means for improving the uniformity, accuracy, and quality of ionizing radiation field measurements. The process is designed to recognize and document the continuing capability of each accredited laboratory to accurately perform instrument calibration. There is no intent to monitor the laboratory to the extent that each calibration can be guaranteed by the program; this responsibility rests solely with the accredited laboratory.

  7. Bartolome Island, Galapagos Stable Oxygen Calibration Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Galapagos Coral Stable Oxygen Calibration Data. Sites: Bartolome Island: 0 deg, 17'S, 90 deg 33' W. Champion Island: 1 deg, 15'S, 90 deg, 05' W. Urvina Bay (Isabela...

  8. Imager for Mars Pathfinder (IMP) image calibration

    Science.gov (United States)

    Reid, R.J.; Smith, P.H.; Lemmon, M.; Tanner, R.; Burkland, M.; Wegryn, E.; Weinberg, J.; Marcialis, R.; Britt, D.T.; Thomas, N.; Kramm, R.; Dummel, A.; Crowe, D.; Bos, B.J.; Bell, J.F.; Rueffer, P.; Gliem, F.; Johnson, J. R.; Maki, J.N.; Herkenhoff, K. E.; Singer, Robert B.

    1999-01-01

    The Imager for Mars Pathfinder returned over 16,000 high-quality images from the surface of Mars. The camera was well-calibrated in the laboratory, with <5% radiometric uncertainty. The photometric properties of two radiometric targets were also measured with 3% uncertainty. Several data sets acquired during the cruise and on Mars confirm that the system operated nominally throughout the course of the mission. Image calibration algorithms were developed for landed operations to correct instrumental sources of noise and to calibrate images relative to observations of the radiometric targets. The uncertainties associated with these algorithms as well as current improvements to image calibration are discussed. Copyright 1999 by the American Geophysical Union.

  9. Calibration of imaging luminance measuring devices (ILMD)

    Science.gov (United States)

    Liu, Liying; Zheng, Feng; Zhu, Lingxi; Li, Ye; Huan, Kewei; Shi, Xiaoguang

    2015-11-01

    A method of calibration of imaging luminance measuring devices has been studied. By the device-independent color space transformation, the color image by digital camera could be converted to the CIE's absolute color space lab. Then, the calibration model is fitted between ln(L/t) and luminance. At last, luminance image is obtained and the dynamic range of luminance image could be adjusted by shutter speed.

  10. Automatic Calibration Of Manual Machine Tools

    Science.gov (United States)

    Gurney, Rex D.

    1990-01-01

    Modified scheme uses data from multiple positions and eliminates tedious positioning. Modification of computer program adapts calibration system for convenient use with manually-controlled machine tools. Developed for use on computer-controlled tools. Option added to calibration program allows data on random tool-axis positions to be entered manually into computer for reduction. Instead of setting axis to predetermined positions, operator merely sets it at variety of arbitrary positions.

  11. Automated intraoperative calibration for prostate cancer brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kuiran Chen, Thomas; Heffter, Tamas; Lasso, Andras; Pinter, Csaba; Abolmaesumi, Purang; Burdette, E. Clif; Fichtinger, Gabor [Queen' s University, Kingston, Ontario K7L 3N6 (Canada); University of British Columbia, Vancouver, British Columbia V6T 1Z4 (Canada); Acoustic MedSystems, Inc., Champaign, Illinois 61820-3979 (United States); Queen' s University, Kingston, Ontario K7L 3N6 (Canada) and Johns Hopkins University, Baltimore, Maryland 21218-2682 (United States)

    2011-11-15

    Purpose: Prostate cancer brachytherapy relies on an accurate spatial registration between the implant needles and the TRUS image, called ''calibration''. The authors propose a new device and a fast, automatic method to calibrate the brachytherapy system in the operating room, with instant error feedback. Methods: A device was CAD-designed and precision-engineered, which mechanically couples a calibration phantom with an exact replica of the standard brachytherapy template. From real-time TRUS images acquired from the calibration device and processed by the calibration system, the coordinate transformation between the brachytherapy template and the TRUS images was computed automatically. The system instantly generated a report of the target reconstruction accuracy based on the current calibration outcome. Results: Four types of validation tests were conducted. First, 50 independent, real-time calibration trials yielded an average of 0.57 {+-} 0.13 mm line reconstruction error (LRE) relative to ground truth. Second, the averaged LRE was 0.37 {+-} 0.25 mm relative to ground truth in tests with six different commercial TRUS scanners operating at similar imaging settings. Furthermore, testing with five different commercial stepper systems yielded an average of 0.29 {+-} 0.16 mm LRE relative to ground truth. Finally, the system achieved an average of 0.56 {+-} 0.27 mm target registration error (TRE) relative to ground truth in needle insertion tests through the template in a water tank. Conclusions: The proposed automatic, intraoperative calibration system for prostate cancer brachytherapy has achieved high accuracy, precision, and robustness.

  12. Sentinel-2 diffuser on-ground calibration

    Science.gov (United States)

    Mazy, E.; Camus, F.; Chorvalli, V.; Domken, I.; Laborie, A.; Marcotte, S.; Stockman, Y.

    2013-10-01

    The Sentinel-2 multi-spectral instrument (MSI) will provide Earth imagery in the frame of the Global Monitoring for Environment and Security (GMES) initiative which is a joint undertaking of the European Commission and the Agency. MSI instrument, under Astrium SAS responsibility, is a push-broom spectro imager in 13 spectral channels in VNIR and SWIR. The instrument radiometric calibration is based on in-flight calibration with sunlight through a quasi Lambertian diffuser. The diffuser covers the full pupil and the full field of view of the instrument. The on-ground calibration of the diffuser BRDF is mandatory to fulfil the in-flight performances. The diffuser is a 779 x 278 mm2 rectangular flat area in Zenith-A material. It is mounted on a motorised door in front of the instrument optical system entrance. The diffuser manufacturing and calibration is under the Centre Spatial of Liege (CSL) responsibility. The CSL has designed and built a completely remote controlled BRDF test bench able to handle large diffusers in their mount. As the diffuser is calibrated directly in its mount with respect to a reference cube, the error budget is significantly improved. The BRDF calibration is performed directly in MSI instrument spectral bands by using dedicated band-pass filters (VNIR and SWIR up to 2200 nm). Absolute accuracy is better than 0.5% in VNIR spectral bands and 1% in SWIR spectral bands. Performances were cross checked with other laboratories. The first MSI diffuser for flight model was calibrated mid 2013 on CSL BRDF measurement bench. The calibration of the diffuser consists mainly in thermal vacuum cycles, BRDF uniformity characterisation and BRDF angular characterisation. The total amount of measurement for the first flight model diffuser corresponds to more than 17500 BRDF acquisitions. Performance results are discussed in comparison with requirements.

  13. Calibration and monitoring for crystal calorimetry

    CERN Document Server

    Zhu, Ren Yuan

    2005-01-01

    Crystal calorimetry provides excellent energy resolution in high energy and nuclear physics. The light output of heavy crystal scintillators, however, suffers from not negligible damage in radiation environment. A precision calibration and monitoring thus is crucial for maintaining crystal precision in situ. The performance of calibration and monitoring approaches used by BaBar, CLEO and L3 experiments are presented. The design and construction of a laser- based light monitoring system for CMS PWO calorimeter is also discussed.

  14. Lidar to lidar calibration phase 1

    DEFF Research Database (Denmark)

    Yordanova, Ginka; Courtney, Michael

    This report presents a feasibility study of a lidar to lidar (L2L) calibration procedure. Phase one of the project was conducted at Høvsøre, Denmark. Two windcubes were placed next to the 116m met mast and different methods were applied to obtain the sensing height error of the lidars. The purpose...... is to find the most consistent method and use it in a potential lidar to lidar calibration procedure....

  15. First results from the MINOS calibration detector

    CERN Document Server

    Vahle, P; Alner, J; Anderson, B; Attree, D; Barker, M; Belias, A; Crone, G; Durkin, T J; Felt, N; Falk, E; Harris, P; Jenner, L; Kordosky, M; Lang, K; Lebedev, A; Lee, R; Longley, N P; Marshak, M; Miyagawa, P; Michael, D G; Morse, R; Musser, J; Nichol, R; Nicholls, T; Oliver, J; Pearce, G; Petyt, D; Proga, M; Rebel, B; Saakyan, R; Smith, C; Sullivan, P; Thomas, J; Weber, A; Wojcicki, S G

    2002-01-01

    The MINOS calibration detector (CalDet) is a small version of the MINOS Near and Far neutrino detectors. A program of exposure to beams of muons, electrons, pions and protons at the CERN PS will provide calibration of the calorimetric and topological response of the Near and Far detectors. In this talk, we briefly discuss the goals and design of the CalDet and present first results from the initial beam exposure. (3 refs).

  16. A Method to Test Model Calibration Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Judkoff, Ron; Polly, Ben; Neymark, Joel

    2016-08-26

    This paper describes a method for testing model calibration techniques. Calibration is commonly used in conjunction with energy retrofit audit models. An audit is conducted to gather information about the building needed to assemble an input file for a building energy modeling tool. A calibration technique is used to reconcile model predictions with utility data, and then the 'calibrated model' is used to predict energy savings from a variety of retrofit measures and combinations thereof. Current standards and guidelines such as BPI-2400 and ASHRAE-14 set criteria for 'goodness of fit' and assume that if the criteria are met, then the calibration technique is acceptable. While it is logical to use the actual performance data of the building to tune the model, it is not certain that a good fit will result in a model that better predicts post-retrofit energy savings. Therefore, the basic idea here is that the simulation program (intended for use with the calibration technique) is used to generate surrogate utility bill data and retrofit energy savings data against which the calibration technique can be tested. This provides three figures of merit for testing a calibration technique, 1) accuracy of the post-retrofit energy savings prediction, 2) closure on the 'true' input parameter values, and 3) goodness of fit to the utility bill data. The paper will also discuss the pros and cons of using this synthetic surrogate data approach versus trying to use real data sets of actual buildings.

  17. "Calibration-on-the-spot'': How to calibrate an EMCCD camera from its images

    DEFF Research Database (Denmark)

    Mortensen, Kim; Flyvbjerg, Henrik

    In localization-based microscopy, super-resolution is obtained by analyzing isolated diffraction-limited spots imaged, typically, with EMCCD cameras. To compare experiments and calculate localization precision, the photon-to-signal amplification factor is needed but unknown without a calibration...... of the camera. Here we show how this can be done post festum from just a recorded image. We demonstrate this (i) theoretically, mathematically, (ii) by analyzing images recorded with an EMCCD camera, and (iii) by analyzing simulated EMCCD images for which we know the true values of parameters. In summary, our...... method of calibration-on-the-spot allows calibration of a camera with unknown settings from old images on file, with no other info needed. Consequently, calibration-on-the-spot also makes future camera calibrations before and after measurements unnecessary, because the calibration is encoded in recorded...

  18. Revised landsat-5 thematic mapper radiometric calibration

    Science.gov (United States)

    Chander, G.; Markham, B.L.; Barsi, J.A.

    2007-01-01

    Effective April 2, 2007, the radiometric calibration of Landsat-5 (L5) Thematic Mapper (TM) data that are processed and distributed by the U.S. Geological Survey (USGS) Center for Earth Resources Observation and Science (EROS) will be updated. The lifetime gain model that was implemented on May 5, 2003, for the reflective bands (1-5, 7) will be replaced by a new lifetime radiometric-calibration curve that is derived from the instrument's response to pseudoinvariant desert sites and from cross calibration with the Landsat-7 (L7) Enhanced TM Plus (ETM+). Although this calibration update applies to all archived and future L5 TM data, the principal improvements in the calibration are for the data acquired during the first eight years of the mission (1984-1991), where the changes in the instrument-gain values are as much as 15%. The radiometric scaling coefficients for bands 1 and 2 for approximately the first eight years of the mission have also been changed. Users will need to apply these new coefficients to convert the calibrated data product digital numbers to radiance. The scaling coefficients for the other bands have not changed. ?? 2007 IEEE.

  19. Calibration facility for environment dosimetry instruments

    Energy Technology Data Exchange (ETDEWEB)

    Bercea, Sorin; Celarel, Aurelia; Cenusa, Constantin [Horia Hulubei National Institute for Physics and Nuclear Engineering, 30 Reactorului St, Magurele, Jud Ilfov, P.O.B. MG-6, RO-077125 (Romania)

    2013-12-16

    In the last ten years, the nuclear activities, as well as the major nuclear events (see Fukushima accident) had an increasing impact on the environment, merely by contamination with radioactive materials. The most conferment way to quickly identify the presence of some radioactive elements in the environment, is to measure the dose-equivalent rate H. In this situation, information concerning the values of H due only to the natural radiation background must exist. Usually, the values of H due to the natural radiation background, are very low (∼10{sup −9} - 10{sup −8} Sv/h). A correct measurement of H in this range involve a performing calibration of the measuring instruments in the measuring range corresponding to the natural radiation background lead to important problems due to the presence of the natural background itself the best way to overlap this difficulty is to set up the calibration stand in an area with very low natural radiation background. In Romania, we identified an area with such special conditions at 200 m dept, in a salt mine. This paper deals with the necessary requirements for such a calibration facility, as well as with the calibration stand itself. The paper includes also, a description of the calibration stand (and images) as well as the radiological and metrological parameters. This calibration facilities for environment dosimetry is one of the few laboratories in this field in Europe.

  20. MODIS Radiometric Calibration Program, Methods and Results

    Science.gov (United States)

    Xiong, Xiaoxiong; Guenther, Bruce; Angal, Amit; Barnes, William; Salomonson, Vincent; Sun, Junqiang; Wenny, Brian

    2012-01-01

    As a key instrument for NASA s Earth Observing System (EOS), the Moderate Resolution Imaging Spectroradiometer (MODIS) has made significant contributions to the remote sensing community with its unprecedented amount of data products continuously generated from its observations and freely distributed to users worldwide. MODIS observations, covering spectral regions from visible (VIS) to long-wave infrared (LWIR), have enabled a broad range of research activities and applications for studies of the earth s interactive system of land, oceans, and atmosphere. In addition to extensive pre-launch measurements, developed to characterize sensor performance, MODIS carries a set of on-board calibrators (OBC) that can be used to track on-orbit changes of various sensor characteristics. Most importantly, dedicated and continuous calibration efforts have been made to maintain sensor data quality. This paper provides an overview of the MODIS calibration program, on-orbit calibration activities, methods, and performance. Key calibration results and lessons learned from the MODIS calibration effort are also presented in this paper.

  1. Atmospheric visibility estimation and image contrast calibration

    Science.gov (United States)

    Hermansson, Patrik; Edstam, Klas

    2016-10-01

    A method, referred to as contrast calibration, has been developed for transforming digital color photos of outdoor scenes from the atmospheric conditions, illumination and visibility, prevailing at the time of capturing the image to a corresponding image for other atmospheric conditions. A photo captured on a hazy day can, for instance, be converted to resemble a photo of the same scene for good visibility conditions. Converting digital color images to specified lightning and transmission conditions is useful for image based assessment of signature suppression solutions. The method uses "calibration objects" which are photographed at about the same time as the scene of interest. The calibration objects, which (indirectly) provide information on visibility and lightning conditions, consist of two flat boards, painted in different grayscale colors, and a commercial, neutral gray, reference card. Atmospheric extinction coefficient and sky intensity can be determined, in three wavelength bands, from image pixel values on the calibration objects and using this information the image can be converted to other atmospheric conditions. The image is transformed in contrast and color. For illustration, contrast calibration is applied to sample images of a scene acquired at different times. It is shown that contrast calibration of the images to the same reference values of extinction coefficient and sky intensity results in images that are more alike than the original images. It is also exemplified how images can be transformed to various other atmospheric weather conditions. Limitations of the method are discussed and possibilities for further development are suggested.

  2. Calibration facility for environment dosimetry instruments

    Science.gov (United States)

    Bercea, Sorin; Celarel, Aurelia; Cenusa, Constantin

    2013-12-01

    In the last ten years, the nuclear activities, as well as the major nuclear events (see Fukushima accident) had an increasing impact on the environment, merely by contamination with radioactive materials. The most conferment way to quickly identify the presence of some radioactive elements in the environment, is to measure the dose-equivalent rate H. In this situation, information concerning the values of H due only to the natural radiation background must exist. Usually, the values of H due to the natural radiation background, are very low (˜10-9 - 10-8 Sv/h). A correct measurement of H in this range involve a performing calibration of the measuring instruments in the measuring range corresponding to the natural radiation background lead to important problems due to the presence of the natural background itself the best way to overlap this difficulty is to set up the calibration stand in an area with very low natural radiation background. In Romania, we identified an area with such special conditions at 200 m dept, in a salt mine. This paper deals with the necessary requirements for such a calibration facility, as well as with the calibration stand itself. The paper includes also, a description of the calibration stand (and images) as well as the radiological and metrological parameters. This calibration facilities for environment dosimetry is one of the few laboratories in this field in Europe.

  3. Calibration of the Hydrological Simulation Program Fortran (HSPF) model using automatic calibration and geographical information systems

    Science.gov (United States)

    Al-Abed, N. A.; Whiteley, H. R.

    2002-11-01

    Calibrating a comprehensive, multi-parameter conceptual hydrological model, such as the Hydrological Simulation Program Fortran model, is a major challenge. This paper describes calibration procedures for water-quantity parameters of the HSPF version 10·11 using the automatic-calibration parameter estimator model coupled with a geographical information system (GIS) approach for spatially averaged properties. The study area was the Grand River watershed, located in southern Ontario, Canada, between 79° 30 and 80° 57W longitude and 42° 51 and 44° 31N latitude. The drainage area is 6965 km2. Calibration efforts were directed to those model parameters that produced large changes in model response during sensitivity tests run prior to undertaking calibration. A GIS was used extensively in this study. It was first used in the watershed segmentation process. During calibration, the GIS data were used to establish realistic starting values for the surface and subsurface zone parameters LZSN, UZSN, COVER, and INFILT and physically reasonable ratios of these parameters among watersheds were preserved during calibration with the ratios based on the known properties of the subwatersheds determined using GIS. This calibration procedure produced very satisfactory results; the percentage difference between the simulated and the measured yearly discharge ranged between 4 to 16%, which is classified as good to very good calibration. The average simulated daily discharge for the watershed outlet at Brantford for the years 1981-85 was 67 m3 s-1 and the average measured discharge at Brantford was 70 m3 s-1. The coupling of a GIS with automatice calibration produced a realistic and accurate calibration for the HSPF model with much less effort and subjectivity than would be required for unassisted calibration.

  4. Chromosome aberration assays in Allium

    Energy Technology Data Exchange (ETDEWEB)

    Grant, W.F.

    1982-01-01

    The common onion (Allium cepa) is an excellent plant for the assay of chromosome aberrations after chemical treatment. Other species of Allium (A. cepa var. proliferum, A. carinatum, A. fistulosum and A. sativum) have also been used but to a much lesser extent. Protocols have been given for using root tips from either bulbs or seeds of Allium cepa to study the cytological end-points, such as chromosome breaks and exchanges, which follow the testing of chemicals in somatic cells. It is considered that both mitotic and meiotic end-points should be used to a greater extent in assaying the cytogenetic effects of a chemical. From a literature survey, 148 chemicals are tabulated that have been assayed in 164 Allium tests for their clastogenic effect. Of the 164 assays which have been carried out, 75 are reported as giving a positive reaction, 49 positive and with a dose response, 1 positive and temperature-related, 9 borderline positive, and 30 negative; 76% of the chemicals gave a definite positive response. It is proposed that the Allium test be included among those tests routinely used for assessing chromosomal damage induced by chemicals.

  5. Disagreement between Human Papillomavirus Assays

    DEFF Research Database (Denmark)

    Rebolj, Matejka; Preisler, Sarah; Ejegod, Ditte Møller;

    2014-01-01

    We aimed to determine the disagreement in primary cervical screening between four human papillomavirus assays: Hybrid Capture 2, cobas, CLART, and APTIMA. Material from 5,064 SurePath samples of women participating in routine cervical screening in Copenhagen, Denmark, was tested with the four ass...

  6. Assessment of assay sensitivity and precision in a malaria antibody ELISA.

    Science.gov (United States)

    Rajasekariah, G Halli R; Kay, Graeme E; Russell, Natrice V; Smithyman, Anthony M

    2003-01-01

    Many types of ELISA-based immunodiagnostic test kits are commercially available in the market for specific indications. These kits provide necessary assay components, reagents, and guidelines to perform the assay under designated optimal conditions. By using these kits, any unknown or test sample can be assessed as negative or positive based on the results of referral calibrator (Ref+ve and Ref-ve) samples. It is essential to provide reliable test kits to end-users with adequate quality control analysis. Therefore, it is necessary to check the kit for any variations in its performance. While developing a malaria antibody ELISA test-kit, we optimized assay conditions with chequer-board analyses and developed an assay protocol. We have taken out kits randomly from the assembly line and had them evaluated by operators who are new to the test-kits. Assays are performed as per the test guidelines provided. Sera, diluted serially, have shown a clear discriminatory signal between a negative vs. positive sample. A COV is determined by evaluating the Ref-ve calibrator in replicate antigen-coated wells from 6 different plates. This COV is used as a tool to determine S/N ratio of test samples. Besides Ref-ve and Ref+ve calibrators, additional field serum samples are tested with the test kit. Several performance indices, such as mean, standard deviation, %CV are calculated, and the inter- and intra-assay variations determined. The assay precision is determined with large and small replicate samples. In addition, assays are performed concurrently in triplicate-, duplicate-, and single-wells, and the results are analyzed for any assay variations. Different plate areas are identified in antigen-coated 96-well plates and tested blind to detect any variations. The S/N ratio is found to be a very effective tool in determining the assay sensitivity. The %CV was within 10-15%. Variations seen in the assays are found to be due to operator errors and not due to kit reagents. These

  7. Monte Carlo Simulations for the Purpose of Efficiency Curve Calibration for the Fastscan Whole Body Counter

    Science.gov (United States)

    Graham, Hannah Robyn

    In order to be able to qualify and quantify radiation exposure in terms of dose, a Fastscan whole body counter must be calibrated correctly. Current calibration methods do not take the full range of body types into consideration when creating efficiency curve calibrations. The goal of this work is the creation of a Monte Carlo (MCNP) model, that allows the simulation of efficiency curves for a diverse population of subjects. Models were created for both the Darlington and the Pickering Fastscan WBCs, and the simulations were benchmarked against experimental results with good agreement. The Pickering Fastscan was found to have agreement to within +/-9%, and the Darlington Fastscan had agreement to within +/-11%. Further simulations were conducted to investigate the effects of increased body fat on the detected activity, as well as locating the position of external contamination using front/back ratios of activity. Simulations were also conducted to create efficiency calibrations that had good agreement with the manufacturer's efficiency curves. The work completed in this thesis can be used to create efficiency calibration curves for unique body compositions in the future.

  8. Optimum Experimental Design applied to MEMS accelerometer calibration for 9-parameter auto-calibration model.

    Science.gov (United States)

    Ye, Lin; Su, Steven W

    2015-01-01

    Optimum Experimental Design (OED) is an information gathering technique used to estimate parameters, which aims to minimize the variance of parameter estimation and prediction. In this paper, we further investigate an OED for MEMS accelerometer calibration of the 9-parameter auto-calibration model. Based on a linearized 9-parameter accelerometer model, we show the proposed OED is both G-optimal and rotatable, which are the desired properties for the calibration of wearable sensors for which only simple calibration devices are available. The experimental design is carried out with a newly developed wearable health monitoring device and desired experimental results have been achieved.

  9. Energy calibration issues in nuclear resonant vibrational spectroscopy: observing small spectral shifts and making fast calibrations.

    Science.gov (United States)

    Wang, Hongxin; Yoda, Yoshitaka; Dong, Weibing; Huang, Songping D

    2013-09-01

    The conventional energy calibration for nuclear resonant vibrational spectroscopy (NRVS) is usually long. Meanwhile, taking NRVS samples out of the cryostat increases the chance of sample damage, which makes it impossible to carry out an energy calibration during one NRVS measurement. In this study, by manipulating the 14.4 keV beam through the main measurement chamber without moving out the NRVS sample, two alternative calibration procedures have been proposed and established: (i) an in situ calibration procedure, which measures the main NRVS sample at stage A and the calibration sample at stage B simultaneously, and calibrates the energies for observing extremely small spectral shifts; for example, the 0.3 meV energy shift between the 100%-(57)Fe-enriched [Fe4S4Cl4](=) and 10%-(57)Fe and 90%-(54)Fe labeled [Fe4S4Cl4](=) has been well resolved; (ii) a quick-switching energy calibration procedure, which reduces each calibration time from 3-4 h to about 30 min. Although the quick-switching calibration is not in situ, it is suitable for normal NRVS measurements.

  10. CALIBRATION OF PANORAMIC CAMERAS WITH CODED TARGETS AND A 3D CALIBRATION FIELD

    Directory of Open Access Journals (Sweden)

    A. M. G. Tommaselli

    2014-03-01

    Full Text Available The aim of this paper is to present results achieved with a 3D terrestrial calibration field, designed for calibrating digital cameras and omnidirectional sensors. This terrestrial calibration field is composed of 139 ARUCO coded targets. Some experiments were performed using a Nikon D3100 digital camera with 8mm Samyang Bower fisheye lens. The camera was calibrated in this terrestrial test field using a conventional bundle adjustment with the Collinearity and mathematical models specially designed for fisheye lenses. The CMC software (Calibration with Multiple Cameras, developed in-house, was used for the calibration trials. This software was modified to use fisheye models to which the Conrady-Brown distortion equations were added. The target identification and image measurements of its four corners were performed automatically with a public software. Several experiments were performed with 16 images and the results were presented and compared. Besides the calibration of fish-eye cameras, the field was designed for calibration of a catadrioptic system and brief informations on the calibration of this unit will be provided in the paper.

  11. Evaluation of 1066 ToxCast Chemicals in a human stem cell assay for developmental toxicity (SOT)

    Science.gov (United States)

    To increase the diversity of assays used to assess potential developmental toxicity, the ToxCast chemical library was screened in the Stemina devTOX quickPREDICT assay using human embryonic stem (hES) cells. A model for predicting teratogenicity was based on a training set of 23 ...

  12. Determining vitamin D status: a comparison between commercially available assays.

    Directory of Open Access Journals (Sweden)

    Greta Snellman

    Full Text Available BACKGROUND: Vitamin D is not only important for bone health but can also affect the development of several non-bone diseases. The definition of vitamin D insufficiency by serum levels of 25-hydroxyvitamin D depends on the clinical outcome but might also be a consequence of analytical methods used for the definition. Although numerous 25-hydroxyvitamin D assays are available, their comparability is uncertain. We therefore aim to investigate the precision, accuracy and clinical consequences of differences in performance between three common commercially available assays. METHODOLOGY/PRINCIPAL FINDINGS: Serum 25-hydroxyvitamin D levels from 204 twins from the Swedish Twin Registry were determined with high-pressure liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (HPLC-APCI-MS, a radioimmunoassay (RIA and a chemiluminescent immunoassay (CLIA. High inter-assay disagreement was found. Mean 25-hydroxyvitamin D levels were highest for the HPLC-APCI-MS technique (85 nmol/L, 95% CI 81-89, intermediate for RIA (70 nmol/L, 95% CI 66-74 and lowest with CLIA (60 nmol/L, 95% CI 56-64. Using a 50-nmol/L cut-off, 8% of the subjects were insufficient using HPLC-APCI-MS, 22% with RIA and 43% by CLIA. Because of the heritable component of 25-hydroxyvitamin D status, the accuracy of each method could indirectly be assessed by comparison of within-twin pair correlations. The strongest correlation was found for HPLC-APCI-MS (r = 0.7, intermediate for RIA (r = 0.5 and lowest for CLIA (r = 0.4. Regression analyses between the methods revealed a non-uniform variance (p<0.0001 depending on level of 25-hydroxyvitamin D. CONCLUSIONS/SIGNIFICANCE: There are substantial inter-assay differences in performance. The most valid method was HPLC-APCI-MS. Calibration between 25-hydroxyvitamin D assays is intricate.

  13. Gender diversity in STEM

    Science.gov (United States)

    Beijerinck, Herman C. W.

    2017-03-01

    There is a strong business case for the value of diversity. Research by the World Economic Forum shows a 36% higher return on equity (ROE) for companies having a workforce with strong gender diversity1. Also growth is influenced in a positive way: in 2009 - 2012 companies with a strong female leadership have increased their ROE by 10.1% as compared to an average of 7.4% for the rest. Diversity is not a problem but a solution!2

  14. Diversity does not travel!

    DEFF Research Database (Denmark)

    Lund, Rebecca; Meriläinen, Susan; Tienari, Janne

    2014-01-01

    In this chapter we offer insights into the social construction of diversity in Finnish organizations and society. In Finnish organizations, gender is highlighted while other markers of diversity are blotted out. 'Non-Finns' become subject to cultural assimilation. The US-based concept of Diversit...... Management becomes adopted and adapted in particular ways. Standardized concepts of diversity and its management do not travel, rather they become translated locally. In organizational practice, globalization is slow and laborious....

  15. Intersectionality, Diversity and Gender

    DEFF Research Database (Denmark)

    Siim, Birte; Agustin, Lise Rolandsen

    2016-01-01

    In the discourses of Danish politicians on ethno-national diversity and integration, the notion of diversity is gendered, especially the articulation of the ‘working woman’ and her labor market participation. Equality, diversity and gender are, thus, intertwined in political, discursive...... constructions of national and European identities/belongings. On this basis the article claims that diversity represents a dual challenge to be conceptualized within and beyond the nation state. The article explores the formation of national and transnational identities based on analyses of political actors...

  16. Premature chromosome condensation (PCC) assay for dose assessment in mass casualty accidents.

    Science.gov (United States)

    Lindholm, Carita; Stricklin, Daniela; Jaworska, Alicja; Koivistoinen, Armi; Paile, Wendla; Arvidsson, Eva; Deperas-Standylo, Joanna; Wojcik, Andrzej

    2010-01-01

    The study was undertaken to establish a dose calibration curve for a practical PCC ring assay and to apply it in a simulated mass casualty accident. The PCC assay was validated against the conventional dicentric assay. A linear relationship was established for PCC rings after (60)Co gamma irradiation with doses up to 20 Gy. In the simulated accident experiment, 62 blood samples were analyzed with both the PCC ring assay and the conventional dicentric assay, applying a triage approach. Samples received various uniform and non-uniform (10-40% partial-body) irradiations up to doses of 13 Gy. The results indicated that both assays yielded good dose estimates for the whole-body exposure scenario, although in the lower-dose range (0-6 Gy) dicentric scoring resulted in more accurate whole-body estimates, whereas PCC rings were better in the high-dose range (>6 Gy). Neither assay was successful in identifying partial-body exposures, most likely due to the low numbers of cells scored in the triage mode. In conclusion, the study confirmed that the PCC ring assay is suitable for use as a biodosimeter after whole-body exposure to high doses of radiation. However, there are limitations for its use in the triage of people exposed to high, partial-body doses.

  17. Implementing a technique to improve the accuracy of shuffler assays of waste drums

    Energy Technology Data Exchange (ETDEWEB)

    Rinard, P.M.

    1996-07-01

    The accuracy of shuffler assays for fissile materials is generally limited by the accuracy of the calibration standards, but when the matrix in a large drum has a sufficiently high hydrogen density (as exists in paper, for example) the accuracy in the active mode can be adversely affected by a nonuniform distribution of the fissile material within the matrix. This paper reports on a technique to determine the distribution nondestructively using delayed neutron signals generated by the shuffler itself. In assays employing this technique, correction factors are applied to the result of the conventional assay according to the distribution. Maximum inaccuracies in assays with a drum of paper, for example, are reduced by a factor of two or three.

  18. An ECVAG trial on assessment of oxidative damage to DNA measured by the comet assay

    DEFF Research Database (Denmark)

    Johansson, Clara; Møller, Peter; Forchhammer, Lykke;

    2010-01-01

    The increasing use of single cell gel electrophoresis (the comet assay) highlights its popularity as a method for detecting DNA damage, including the use of enzymes for assessment of oxidatively damaged DNA. However, comparison of DNA damage levels between laboratories can be difficult due...... assay end points to number of lesions/10(6) bp by calibration with ionizing radiation. The aim of this study was to investigate the inter-laboratory variation in assessment of oxidatively damaged DNA by the comet assay in terms of oxidized purines converted to strand breaks with formamidopyrimidine DNA...... to differences in assay protocols (e.g. lysis conditions, enzyme treatment, the duration of the alkaline treatment and electrophoresis) and in the end points used for reporting results (e.g. %DNA in tail, arbitrary units, tail moment and tail length). One way to facilitate comparisons is to convert primary comet...

  19. 21 CFR 225.158 - Laboratory assays.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Laboratory assays. 225.158 Section 225.158 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS... Laboratory assays. Where the results of laboratory assays of drug components, including assays by State...

  20. Microhotplate Temperature Sensor Calibration and BIST.

    Science.gov (United States)

    Afridi, M; Montgomery, C; Cooper-Balis, E; Semancik, S; Kreider, K G; Geist, J

    2011-01-01

    In this paper we describe a novel long-term microhotplate temperature sensor calibration technique suitable for Built-In Self Test (BIST). The microhotplate thermal resistance (thermal efficiency) and the thermal voltage from an integrated platinum-rhodium thermocouple were calibrated against a freshly calibrated four-wire polysilicon microhotplate-heater temperature sensor (heater) that is not stable over long periods of time when exposed to higher temperatures. To stress the microhotplate, its temperature was raised to around 400 °C and held there for days. The heater was then recalibrated as a temperature sensor, and microhotplate temperature measurements were made based on the fresh calibration of the heater, the first calibration of the heater, the microhotplate thermal resistance, and the thermocouple voltage. This procedure was repeated 10 times over a period of 80 days. The results show that the heater calibration drifted substantially during the period of the test while the microhotplate thermal resistance and the thermocouple-voltage remained stable to within about plus or minus 1 °C over the same period. Therefore, the combination of a microhotplate heater-temperature sensor and either the microhotplate thermal resistance or an integrated thin film platinum-rhodium thermocouple can be used to provide a stable, calibrated, microhotplate-temperature sensor, and the combination of the three sensor is suitable for implementing BIST functionality. Alternatively, if a stable microhotplate-heater temperature sensor is available, such as a properly annealed platinum heater-temperature sensor, then the thermal resistance of the microhotplate and the electrical resistance of the platinum heater will be sufficient to implement BIST. It is also shown that aluminum- and polysilicon-based temperature sensors, which are not stable enough for measuring high microhotplate temperatures (>220 °C) without impractically frequent recalibration, can be used to measure the

  1. Exploration of new multivariate spectral calibration algorithms.

    Energy Technology Data Exchange (ETDEWEB)

    Van Benthem, Mark Hilary; Haaland, David Michael; Melgaard, David Kennett; Martin, Laura Elizabeth; Wehlburg, Christine Marie; Pell, Randy J. (The Dow Chemical Company, Midland, MI); Guenard, Robert D. (Merck & Co. Inc., West Point, PA)

    2004-03-01

    A variety of multivariate calibration algorithms for quantitative spectral analyses were investigated and compared, and new algorithms were developed in the course of this Laboratory Directed Research and Development project. We were able to demonstrate the ability of the hybrid classical least squares/partial least squares (CLSIPLS) calibration algorithms to maintain calibrations in the presence of spectrometer drift and to transfer calibrations between spectrometers from the same or different manufacturers. These methods were found to be as good or better in prediction ability as the commonly used partial least squares (PLS) method. We also present the theory for an entirely new class of algorithms labeled augmented classical least squares (ACLS) methods. New factor selection methods are developed and described for the ACLS algorithms. These factor selection methods are demonstrated using near-infrared spectra collected from a system of dilute aqueous solutions. The ACLS algorithm is also shown to provide improved ease of use and better prediction ability than PLS when transferring calibrations between near-infrared calibrations from the same manufacturer. Finally, simulations incorporating either ideal or realistic errors in the spectra were used to compare the prediction abilities of the new ACLS algorithm with that of PLS. We found that in the presence of realistic errors with non-uniform spectral error variance across spectral channels or with spectral errors correlated between frequency channels, ACLS methods generally out-performed the more commonly used PLS method. These results demonstrate the need for realistic error structure in simulations when the prediction abilities of various algorithms are compared. The combination of equal or superior prediction ability and the ease of use of the ACLS algorithms make the new ACLS methods the preferred algorithms to use for multivariate spectral calibrations.

  2. Calibration of mass spectrometric peptide mass fingerprint data without specific external or internal calibrants

    Directory of Open Access Journals (Sweden)

    Lalowski Maciej

    2005-08-01

    Full Text Available Abstract Background Peptide Mass Fingerprinting (PMF is a widely used mass spectrometry (MS method of analysis of proteins and peptides. It relies on the comparison between experimentally determined and theoretical mass spectra. The PMF process requires calibration, usually performed with external or internal calibrants of known molecular masses. Results We have introduced two novel MS calibration methods. The first method utilises the local similarity of peptide maps generated after separation of complex protein samples by two-dimensional gel electrophoresis. It computes a multiple peak-list alignment of the data set using a modified Minimum Spanning Tree (MST algorithm. The second method exploits the idea that hundreds of MS samples are measured in parallel on one sample support. It improves the calibration coefficients by applying a two-dimensional Thin Plate Splines (TPS smoothing algorithm. We studied the novel calibration methods utilising data generated by three different MALDI-TOF-MS instruments. We demonstrate that a PMF data set can be calibrated without resorting to external or relying on widely occurring internal calibrants. The methods developed here were implemented in R and are part of the BioConductor package mscalib available from http://www.bioconductor.org. Conclusion The MST calibration algorithm is well suited to calibrate MS spectra of protein samples resulting from two-dimensional gel electrophoretic separation. The TPS based calibration algorithm might be used to correct systematic mass measurement errors observed for large MS sample supports. As compared to other methods, our combined MS spectra calibration strategy increases the peptide/protein identification rate by an additional 5 – 15%.

  3. Development and validation of a multiplex add-on assay of biomarkers related to sepsis using xMAP technology

    DEFF Research Database (Denmark)

    Kofoed, Kristian; Vest Schneider, Uffe; Scheel, Troels

    2006-01-01

    %, respectively. Recoveries of suPAR, sTREM-1, and MIF calibrators were 108%, 88%, and 51%, respectively. In plasma collected from 10 patients with bacterial sepsis confirmed by blood culture, the assay detected significantly increased concentrations of all 8 analytes compared with healthy controls. CONCLUSIONS...

  4. Development and validation of a multiplex add-on assay for sepsis biomarkers using xMAP technology

    DEFF Research Database (Denmark)

    Kofoed, Kristian; Schneider, Uffe Vest; Scheel, Troels

    2006-01-01

    %, respectively. Recoveries of suPAR, sTREM-1, and MIF calibrators were 108%, 88%, and 51%, respectively. In plasma collected from 10 patients with bacterial sepsis confirmed by blood culture, the assay detected significantly increased concentrations of all 8 analytes compared with healthy controls. CONCLUSIONS...

  5. Low-energy ED-XRF spectrometry application in gold assaying

    Energy Technology Data Exchange (ETDEWEB)

    Marucco, Alessandra E-mail: marucco@itia.cnr.it

    2004-01-01

    The performances of a low-energy dispersive XRF spectrometer in gold assaying are evaluated by a series of analysis on international standards and other certified gold alloys with. Results of standard-free analysis based on fundamental parameters method compared to results of multi-standard method, demonstrate a large gain of accuracy by drawing appropriate calibration curves with use of 1 to 16 matrix-specific standards. The accuracy of gold assaying has improved by a factor of 10, as compared to the conventional touchstone test. This rather economical technique satisfies then numerous precious alloys analyst needs, representing an excellent alternative to the traditional method for quick anti-fraud controls.

  6. The skin-blanching assay.

    Science.gov (United States)

    Smit, P; Neumann, H A M; Thio, H B

    2012-10-01

    The skin-blanching assay is used for the determination and bioequivalence of dermatologic glucocorticoids (GCs). The exact mechanism of the production of blanching is not fully understood, but it is considered that local vasoconstriction of the skin microvasculature and the consequent blood-flow reduction cause this phenomenon. Several factors influence skin blanching, including drug concentration, duration of application, nature of vehicle, occlusion, posture and location. The intensity of vasoconstriction can be measured in several ways: visual or quantitative methods, such as reflectance spectroscopy, thermography, laser Doppler velocimetry and chromametry. In literature, contradicting results in the correlation of the skin-blanching assay with different tests to determine GC sensitivity have been reported, limiting its clinical usefulness.

  7. Comet Assay in Cancer Chemoprevention.

    Science.gov (United States)

    Santoro, Raffaela; Ferraiuolo, Maria; Morgano, Gian Paolo; Muti, Paola; Strano, Sabrina

    2016-01-01

    The comet assay can be useful in monitoring DNA damage in single cells caused by exposure to genotoxic agents, such as those causing air, water, and soil pollution (e.g., pesticides, dioxins, electromagnetic fields) and chemo- and radiotherapy in cancer patients, or in the assessment of genoprotective effects of chemopreventive molecules. Therefore, it has particular importance in the fields of pharmacology and toxicology, and in both environmental and human biomonitoring. It allows the detection of single strand breaks as well as double-strand breaks and can be used in both normal and cancer cells. Here we describe the alkali method for comet assay, which allows to detect both single- and double-strand DNA breaks.

  8. Astrometric Calibration of the Gemini Planet Imager

    Science.gov (United States)

    Tran, Debby; Konopacky, Quinn M.; GPIES Team

    2017-01-01

    The Gemini Planet Imager (GPI), housed on the 8-meter Gemini South telescope in Chile, is an instrument designed to detect Jupiter-like extrasolar planets by direct imaging. It relies on adaptive optics to correct the effects of atmospheric turbulence, along with an advanced coronagraph and calibration system. One of the scientific goals of GPI is to measure the orbital properties of the planets it discovers. Because these orbits have long periods, precise measurements of the relative position between the star and the planet (relative astrometry) are required. In this poster, I will present the astrometric calibration of GPI. We constrain the plate scale and orientation of the camera by observing different binary star systems with both GPI and another well-calibrated instrument, NIRC2, at the Keck telescope in Hawaii. We measure their separations with both instruments and use that information to calibrate the plate scale. By taking these calibration measurements over the course of one year, we have measured the plate scale to 0.05% and shown that it is stable across multiple epochs. We also examined the effects of the point spread function on the positions of the binaries as well as their separations, the results of which I will discuss.

  9. Adaptable Multivariate Calibration Models for Spectral Applications

    Energy Technology Data Exchange (ETDEWEB)

    THOMAS,EDWARD V.

    1999-12-20

    Multivariate calibration techniques have been used in a wide variety of spectroscopic situations. In many of these situations spectral variation can be partitioned into meaningful classes. For example, suppose that multiple spectra are obtained from each of a number of different objects wherein the level of the analyte of interest varies within each object over time. In such situations the total spectral variation observed across all measurements has two distinct general sources of variation: intra-object and inter-object. One might want to develop a global multivariate calibration model that predicts the analyte of interest accurately both within and across objects, including new objects not involved in developing the calibration model. However, this goal might be hard to realize if the inter-object spectral variation is complex and difficult to model. If the intra-object spectral variation is consistent across objects, an effective alternative approach might be to develop a generic intra-object model that can be adapted to each object separately. This paper contains recommendations for experimental protocols and data analysis in such situations. The approach is illustrated with an example involving the noninvasive measurement of glucose using near-infrared reflectance spectroscopy. Extensions to calibration maintenance and calibration transfer are discussed.

  10. PHOTOMETRYPIPELINE: An automated pipeline for calibrated photometry

    Science.gov (United States)

    Mommert, M.

    2017-01-01

    PHOTOMETRYPIPELINE (PP) is an automated pipeline that produces calibrated photometry from imaging data through image registration, aperture photometry, photometric calibration, and target identification with only minimal human interaction. PP utilizes the widely used Source Extractor software for source identification and aperture photometry; SCAMP is used for image registration. Both image registration and photometric calibration are based on matching field stars with star catalogs, requiring catalog coverage of the respective field. A number of different astrometric and photometric catalogs can be queried online. Relying on a sufficient number of background stars for image registration and photometric calibration, PP is well-suited to analyze data from small to medium-sized telescopes. Calibrated magnitudes obtained by PP are typically accurate within ≤0.03 mag and astrometric accuracies are of the order of 0.3 arcsec relative to the catalogs used in the registration. The pipeline consists of an open-source software suite written in Python 2.7, can be run on Unix-based systems on a simple desktop machine, and is capable of realtime data analysis. PP has been developed for observations of moving targets, but can be used for analyzing point source observations of any kind.

  11. A Unifying Theory for Camera Calibration.

    Science.gov (United States)

    Ramalingam, SriKumar; Sturm, Peter

    2016-07-19

    This paper proposes a unified theory for calibrating a wide variety of camera models such as pinhole, fisheye, cata-dioptric, and multi-camera networks. We model any camera as a set of image pixels and their associated camera rays in space. Every pixel measures the light traveling along a (half-) ray in 3-space, associated with that pixel. By this definition, calibration simply refers to the computation of the mapping between pixels and the associated 3D rays. Such a mapping can be computed using images of calibration grids, which are objects with known 3D geometry, taken from unknown positions. This general camera model allows to represent non-central cameras; we also consider two special subclasses, namely central and axial cameras. In a central camera, all rays intersect in a single point, whereas the rays are completely arbitrary in a non-central one. Axial cameras are an intermediate case: the camera rays intersect a single line. In this work, we show the theory for calibrating central, axial and non-central models using calibration grids, which can be either three-dimensional or planar.

  12. SCIAMACHY Level 1 data: calibration concept and in-flight calibration

    NARCIS (Netherlands)

    Lichtenberg, G.; Kleipool, Q.; Krijger, J.M.; Soest, G. van; Hees, R. van; Tilstra, L.G.; Acarreta, J.R.; Aben, I.; Ahlers, B.; Bovensmann, H.; Chance, K.; Gloudemans, A.M.S.; Hoogeveen, R.W.M.; Jongma, R.T.N.; Noël, S.; Piters, A.; Schrijver, H.; Schrijvers, C.; Sioris, C.E.; Skupin, J.; Slijkhuis, S.; Stammes, P.; Wuttke, M.

    2006-01-01

    The calibration of SCIAMACHY was thoroughly checked since the instrument was launched on-board ENVISAT in February 2002. While SCIAMACHY's functional performance is excellent since launch, a number of technical difficulties have appeared, that required adjustments to the calibration. The problems ca

  13. Protein binding assay for hyaluronate

    Energy Technology Data Exchange (ETDEWEB)

    Lacy, B.E.; Underhill, C.B.

    1986-11-01

    A relatively quick and simple assay for hyaluronate was developed using the specific binding protein, hyaluronectin. The hyaluronectin was obtained by homogenizing the brains of Sprague-Dawley rats, and then centrifuging the homogenate. The resulting supernatant was used as a source of crude hyaluronectin. In the binding assay, the hyaluronectin was mixed with (/sup 3/H)hyaluronate, followed by an equal volume of saturated (NH/sub 4/)/sub 2/SO/sub 4/, which precipitated the hyaluronectin and any (/sup 3/H)hyaluronate associated with it, but left free (/sup 3/H)hyaluronate in solution. The mixture was then centrifuged, and the amount of bound (/sup 3/H)hyaluronate in the precipitate was determined. Using this assay, the authors found that hyaluronectin specifically bound hyaluronate, since other glycosaminoglycans failed to compete for the binding protein. In addition, the interaction between hyaluronectin and hyaluronate was of relatively high affinity, and the size of the hyaluronate did not appear to substantially alter the amount of binding. To determine the amount of hyaluronate in an unknown sample, they used a competition assay in which the binding of a set amount of (/sup 3/H)hyaluronate was blocked by the addition of unlabeled hyaluronate. By comparing the degree of competition of the unknown samples with that of known amounts of hyaluronate, it was possible to determine the amount of hyaluronate in the unknowns. They have found that this method is sensitive to 1 ..mu..g or less of hyaluronate, and is unaffected by the presence of proteins.

  14. Bioluminescence assay for cell viability.

    Science.gov (United States)

    Lomakina, G Yu; Modestova, Yu A; Ugarova, N N

    2015-06-01

    Theoretical aspects of the adenosine triphosphate bioluminescence assay based on the use of the firefly luciferin-luciferase system are considered, as well as its application for assessing cell viability in microbiology, sanitation, medicine, and ecology. Various approaches for the analysis of individual or mixed cultures of microorganisms are presented, and capabilities of the method for investigation of biological processes in live cells including necrosis, apoptosis, as well as for investigation of the dynamics of metabolism are described.

  15. Fluorescence Polarization Assays in Small Molecule Screening

    Science.gov (United States)

    Lea, Wendy A.; Simeonov, Anton

    2011-01-01

    Importance of the field Fluorescence polarization (FP) is a homogeneous method that allows rapid and quantitative analysis of diverse molecular interactions and enzyme activities. This technique has been widely utilized in clinical and biomedical settings, including the diagnosis of certain diseases and monitoring therapeutic drug levels in body fluids. Recent developments in the field has been symbolized by the facile adoption of FP in high-throughput screening (HTS) and small molecule drug discovery of an increasing range of target classes. Areas covered in this review The article provides a brief overview on the theoretical foundation of FP, followed by updates on recent advancements in its application for various drug target classes, including G-protein coupled receptors (GPCRs), enzymes and protein-protein interactions (PPIs). The strengths and weaknesses of this method, practical considerations in assay design, novel applications, and future directions are also discussed. What the reader will gain The reader will be informed of the most recent advancements and future directions of FP application to small molecule screening. Take home message In addition to its continued utilization in high-throughput screening, FP has expanded into new disease and target areas and has been marked by increased use of labeled small molecule ligands for receptor binding studies. PMID:22328899

  16. Diversity and Social Cohesion

    Science.gov (United States)

    Pagani, Camilla

    2014-01-01

    The issue of diversity, in its broadest sense, is discussed here in its relation to social cohesion, cross-cultural relations, ingroup-outgroup relations and educational interventions. The main thesis of the paper is that real social cohesion in an ingroup rests on the acknowledgment of and the dialog with the diversities of the members of the…

  17. The Diversity Machine.

    Science.gov (United States)

    Lynch, Frederick R.

    1997-01-01

    Discusses social policy influences on the workplace and how the linkage of demographic change with multiculturalism has led to changes in organizational policies. It examines the emergence of diversity management practice, the influence of globalizing markets in driving corporate diversity policies, and the roles of corporate and government…

  18. Putting Diversity to Work

    DEFF Research Database (Denmark)

    Holck, Lotte

    2016-01-01

    Purpose: The purpose of this article is to critically explore why a diversity agenda in favor of equal opportunities failed despite apparent organizational support and commitment to diversity. Design/methodology/approach: Drawing on data from a municipal center, this study inquires into how organ...

  19. An Optimal Calibration Method for a MEMS Inertial Measurement Unit

    Directory of Open Access Journals (Sweden)

    Bin Fang

    2014-02-01

    Full Text Available An optimal calibration method for a micro-electro-mechanical inertial measurement unit (MIMU is presented in this paper. The accuracy of the MIMU is highly dependent on calibration to remove the deterministic errors of systematic errors, which also contain random errors. The overlapping Allan variance is applied to characterize the types of random error terms in the measurements. The calibration model includes package misalignment error, sensor-to-sensor misalignment error and bias, and a scale factor is built. The new concept of a calibration method, which includes a calibration scheme and a calibration algorithm, is proposed. The calibration scheme is designed by D-optimal and the calibration algorithm is deduced by a Kalman filter. In addition, the thermal calibration is investigated, as the bias and scale factor varied with temperature. The simulations and real tests verify the effectiveness of the proposed calibration method and show that it is better than the traditional method.

  20. A simple micro-extraction plate assay for automated LC-MS/MS analysis of human serum 25-hydroxyvitamin D levels.

    Science.gov (United States)

    Geib, Timon; Meier, Florian; Schorr, Pascal; Lammert, Frank; Stokes, Caroline S; Volmer, Dietrich A

    2015-01-01

    This short application note describes a simple and automated assay for determination of 25-hydroxyvitamin D (25(OH)D) levels in very small volumes of human serum. It utilizes commercial 96-well micro-extraction plates with commercial 25(OH)D isotope calibration and quality control kits. Separation was achieved using a pentafluorophenyl liquid chromatography column followed by multiple reaction monitoring-based quantification on an electrospray triple quadrupole mass spectrometer. Emphasis was placed on providing a simple assay that can be rapidly established in non-specialized laboratories within days, without the need for laborious and time consuming sample preparation steps, advanced calibration or data acquisition routines. The analytical figures of merit obtained from this assay compared well to established assays. To demonstrate the applicability, the assay was applied to analysis of serum samples from patients with chronic liver diseases and compared to results from a routine clinical immunoassay.

  1. The marine diversity spectrum

    DEFF Research Database (Denmark)

    Reuman, Daniel C.; Gislason, Henrik; Barnes, Carolyn

    2014-01-01

    of taxonomy (all the species in a region regardless of clade) are much less studied but are equally important and will illuminate a different set of ecological and evolutionary processes. We develop and test a mechanistic model of how diversity varies with body mass in marine ecosystems. The model predicts...... the form of the diversity spectrum', which quantifies the distribution of species' asymptotic body masses, is a species analogue of the classic size spectrum of individuals, and which we have found to be a new and widely applicable description of diversity patterns. The marine diversity spectrum...... is predicted to be approximately linear across an asymptotic mass range spanning seven orders of magnitude. Slope -0 center dot 5 is predicted for the global marine diversity spectrum for all combined pelagic zones of continental shelf seas, and slopes for large regions are predicted to lie between -0 center...

  2. Managing Protean Diversity

    DEFF Research Database (Denmark)

    Marfelt, Mikkel Mouritz; Muhr, Sara Louise

    2016-01-01

    . In this article, we follow the call for critically investigating the contexts influencing diversity management by analyzing the development of a global human resource management project initiated to promote a culturally diverse workforce. We find that despite good intentions, as well as support from the top......Recently, global workforce diversity and its management have received criticism for not paying attention to the contextual influence stemming from socially constructed dialectics of power and politics. These contextual dynamics, however, tend to be viewed as external to the organization...... management, the project dissolves through micropolitics and power dynamics. We contribute to the critical literature on workforce diversity by identifying how organizational contextual dynamics influence the way the concept of workforce diversity is constructed and understood at work. Based on these findings...

  3. Trainee Readiness For Diversity Training

    Directory of Open Access Journals (Sweden)

    Yunhyung Chung

    2013-11-01

    Full Text Available Although trainee readiness is critical for diversity training effectiveness, extant research has not paid attention to the relationship between trainee readiness for diversity training and diversity training outcomes. This study identifies motivational, behavioral, and cognitive trainee readiness for diversity training and proposes a theoretical framework of how individual characteristics (perceived discrimination, demographic attributes, and previous diversity-related experience and organizational characteristics (diversity climate and demographic dissimilarity influence motivational, behavioral, and cognitive trainee readiness for diversity training.

  4. A Review of Sensor Calibration Monitoring for Calibration Interval Extension in Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Coble, Jamie B.; Meyer, Ryan M.; Ramuhalli, Pradeep; Bond, Leonard J.; Hashemian, Hash; Shumaker, Brent; Cummins, Dara

    2012-08-31

    Currently in the United States, periodic sensor recalibration is required for all safety-related sensors, typically occurring at every refueling outage, and it has emerged as a critical path item for shortening outage duration in some plants. Online monitoring can be employed to identify those sensors that require calibration, allowing for calibration of only those sensors that need it. International application of calibration monitoring, such as at the Sizewell B plant in United Kingdom, has shown that sensors may operate for eight years, or longer, within calibration tolerances. This issue is expected to also be important as the United States looks to the next generation of reactor designs (such as small modular reactors and advanced concepts), given the anticipated longer refueling cycles, proposed advanced sensors, and digital instrumentation and control systems. The U.S. Nuclear Regulatory Commission (NRC) accepted the general concept of online monitoring for sensor calibration monitoring in 2000, but no U.S. plants have been granted the necessary license amendment to apply it. This report presents a state-of-the-art assessment of online calibration monitoring in the nuclear power industry, including sensors, calibration practice, and online monitoring algorithms. This assessment identifies key research needs and gaps that prohibit integration of the NRC-approved online calibration monitoring system in the U.S. nuclear industry. Several needs are identified, including the quantification of uncertainty in online calibration assessment; accurate determination of calibration acceptance criteria and quantification of the effect of acceptance criteria variability on system performance; and assessment of the feasibility of using virtual sensor estimates to replace identified faulty sensors in order to extend operation to the next convenient maintenance opportunity. Understanding the degradation of sensors and the impact of this degradation on signals is key to

  5. Pulsed thrust measurements using electromagnetic calibration techniques

    Energy Technology Data Exchange (ETDEWEB)

    Tang Haibin; Shi Chenbo; Zhang Xin' ai; Zhang Zun; Cheng Jiao [School of Astronautics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China)

    2011-03-15

    A thrust stand for accurately measuring impulse bits, which ranged from 10-1000 {mu}N s using a noncontact electromagnetic calibration technique is described. In particular, a permanent magnet structure was designed to produce a uniform magnetic field, and a multiturn coil was made to produce a calibration force less than 10 mN. The electromagnetic calibration force for pulsed thrust measurements was linear to the coil current and changed less than 2.5% when the distance between the coil and magnet changed 6 mm. A pulsed plasma thruster was first tested on the thrust stand, and afterward five single impulse bits were measured to give a 310 {mu}N s average impulse bit. Uncertainty of the measured impulse bit was analyzed to evaluate the quality of the measurement and was found to be 10 {mu}N s with 95% credibility.

  6. The Berkeley extreme ultraviolet calibration facility

    Science.gov (United States)

    Welsh, Barry Y.; Jelinsky, Patrick; Malina, Roger F.

    1988-01-01

    The vacuum calibration facilities of the Space Sciences Laboratory, University of California at Berkeley are designed for the calibration and testing of EUV and FUV spaceborne instrumentation (spectral range 44-2500 A). The facility includes one large cylindrical vacuum chamber (3 x 5 m) containing two EUV collimators, and it is equipped with a 4-axis manipulator of angular-control resolution 1 arcsec for payloads weighing up to 500 kg. In addition, two smaller cylindrical chambers, each 0.9 x 1.2 m, are available for vacuum and thermal testing of UV detectors, filters, and space electronics hardware. All three chambers open into class-10,000 clean rooms, and all calibrations are referred to NBS secondary standards.

  7. Muon Calibration at SoLid

    CERN Document Server

    Saunders, Daniel

    2016-01-01

    The SoLid experiment aims to make a measurement of very short distance neutrino oscillations using reactor antineutrinos. Key to its sensitivity are the experiments high spatial and energy resolution, combined with a very suitable reactor source and efficient background rejection. The fine segmentation of the detector (cubes of side 5cm), and ability to resolve signals in space and time, gives SoLid the capability to track cosmic muons. In principle a source of background, these turn into a valuable calibration source if they can be cleanly identified. This work presents the first energy calibration results, using cosmic muons, of the 288kg SoLid prototype SM1. This includes the methodology of tracking at SoLid, cosmic ray angular analyses at the reactor site, estimates of the time resolution, and calibrations at the cube level.

  8. Generic methodology for calibrating profiling nacelle lidars

    DEFF Research Database (Denmark)

    Borraccino, Antoine; Courtney, Michael; Wagner, Rozenn

    Improving power performance assessment by measuring at different heights has been demonstrated using ground-based profiling LIDARs. More recently, nacelle-mounted lidars studies have shown promising capabilities to assess power performance. Using nacelle lidars avoids the erection of expensive...... meteorology masts, especially offshore. A new generation of commercially developed profiling nacelle lidars has sophisticated measurement capabilities. As for any other measuring system, lidars measurements have uncertainties. Their estimation is the ultimate goal of a calibration. Field calibration...... procedures have been developed for non-profiling nacelle lidars. However, their specificity to one type of lidar or another highlights the need for developing generic calibration procedures. Such procedures should be applicable to any type of existing and upcoming lidar technology. Profiling nacelle lidars...

  9. Colorimetric calibration of coupled infrared simulation system

    Science.gov (United States)

    Zhang, Ying; Fei, Jindong; Gao, Yang; Du, Jian

    2015-10-01

    In order to test 2-color infrared sensors, a coupled infrared simulation system can generate radiometric outputs with wavelengths that range from less than 3 microns to more than 12 microns. There are two channels in the coupled simulation system, optically combined by a diachronic beam combiner. Each channel has an infrared blackbody, a filter, a diaphragm, and diaphragm-motors. The system is projected to the sensor under testing by a collimator. This makes it difficult to calibrate the system with only one-band thermal imager. Errors will be caused in the radiance levels measured by the narrow band thermal imager. This paper describes colorimetric temperature measurement techniques that have been developed to perform radiometric calibrations of these infrared simulation systems above. The calibration system consists of two infrared thermal imagers; one is operated at the wavelength range of MW-IR, and the other at the range of LW-IR.

  10. Auroral meridian scanning photometer calibration using Jupiter

    Science.gov (United States)

    Jackel, Brian J.; Unick, Craig; Creutzberg, Fokke; Baker, Greg; Davis, Eric; Donovan, Eric F.; Connors, Martin; Wilson, Cody; Little, Jarrett; Greffen, M.; McGuffin, Neil

    2016-10-01

    Observations of astronomical sources provide information that can significantly enhance the utility of auroral data for scientific studies. This report presents results obtained by using Jupiter for field cross calibration of four multispectral auroral meridian scanning photometers during the 2011-2015 Northern Hemisphere winters. Seasonal average optical field-of-view and local orientation estimates are obtained with uncertainties of 0.01 and 0.1°, respectively. Estimates of absolute sensitivity are repeatable to roughly 5 % from one month to the next, while the relative response between different wavelength channels is stable to better than 1 %. Astronomical field calibrations and darkroom calibration differences are on the order of 10 %. Atmospheric variability is the primary source of uncertainty; this may be reduced with complementary data from co-located instruments.

  11. Calibration Results Of The Strofio Sensor

    Science.gov (United States)

    Livi, S. A.; Allegrini, F.; Miles, P. F.

    2013-12-01

    The sensor Strofio is a mass spectrometer, part of the Serena plasma/neutral particles package for the BepiColombo mission to Mercury. During several campaignes of calibraion at the Southwest Research Institute and at the University of Bern we calibrated the characteristics of the Flight Unit and determined the calibration factors of the sensor. All the measured responses of Strofio to external stimuly are compatible with the requirements necessary to characterize the tenuous exosphere of Mercury. In the measured particluar sensitivity (0.14 (cts/sec)/(1/cm3)), resolution (m/dm>90), mass range (4-60 + 80-120) and capability of background rejection ( > 40) are well fitted to the expected conditions around the planet. We present the current understanding of composition and variability of the Hemean exosphere, the derived physical measurables, and show the relevant Strofio calibration results.

  12. Calibrating transport lines using LOCO techniques

    Energy Technology Data Exchange (ETDEWEB)

    Yves Roblin

    2011-09-01

    With the 12GeV upgrade underway at CEBAF, there is a need to re-characterize the beamlines after the modifications made to it to accommodate running at higher energies. We present a linear perturbation approach to calibrating the optics model of transport lines. This method is adapted from the LOCO method in use for storage rings. We consider the effect of quadrupole errors, dipole construction errors as well as beam position monitors and correctors calibrations. The ideal model is expanded to first order in Taylor series of the quadrupole errors. A set of difference orbits obtained by exciting the correctors along the beamline is taken, yielding the measured response matrix. An iterative procedure is invoked and the quadrupole errors as well as beam position monitors and corrector calibration factors are obtained. Here we present details of the method and results of first measurements at CEBAF in early 2011.

  13. A Calibrating Device for Rogowski Coil Development

    Institute of Scientific and Technical Information of China (English)

    LV Liang; LI Junhao; HUANG Jianjun; JI Shengchang; LI Yanming

    2007-01-01

    A calibrating device for the Rogowski coil is developed,which can be used to calibrate the Rogowski coil having a partial response time within tens of nanoseconds.Its key component is a step current generator,which can generate the output with a rise time of less than 2 ns and a duration of larger than 300 ns.The step current generator is composed by a pulse forming line(PFL)and a pulse transmission line(PTL).A TEM(transverse electromagnetic mode)coaxial measurement unit is used as PTL,and the coil to be calibrated and the referenced standard Rogowski coil can be fixed in the unit.The effect of the dimensions of the TEM unit is discussed theoretically as well as experimentally.

  14. ATLAS Tile calorimeter calibration and monitoring systems

    CERN Document Server

    Chomont, Arthur Rene; The ATLAS collaboration

    2016-01-01

    The ATLAS Tile Calorimeter (TileCal) is the central section of the hadronic calorimeter of the ATLAS experiment and provides important information for reconstruction of hadrons, jets, hadronic decays of tau leptons and missing transverse energy. This sampling calorimeter uses steel plates as absorber and scintillating tiles as active medium. The light produced by the passage of charged particles is transmitted by wavelength shifting fibres to photomultiplier tubes (PMTs), located on the outside of the calorimeter. The readout is segmented into about 5000 cells (longitudinally and transversally), each of them being read out by two PMTs in parallel. To calibrate and monitor the stability and performance of each part of the readout chain during the data taking, a set of calibration systems is used. The TileCal calibration system comprises Cesium radioactive sources, laser and charge injection elements and it allows to monitor and equalize the calorimeter response at each stage of the signal production, from scin...

  15. Artificial calibration source for ALMA radio interferometer

    Science.gov (United States)

    Kiuchi, Hitoshi; Hills, Richard; Whyborn, Nicholas D.; Asayama, Shinichiro; Sakamoto, Seiichi; Iguchi, Satoru; Corder, Stuartt A.

    2016-07-01

    The ALMA (Atacama Large Millimeter/submillimeter Array) radio interferometer has some different types of antennas which have a variation of gain and leakages across the primary beam of an individual antenna. We have been developing an artificial calibration source which is used for compensation of individual difference of antennas. In a high-frequency antenna, using astronomical sources to do calibration measurement would be extremely time consuming, whereas with the artificial calibration source becomes a realistic possibility. Photonic techniques are considered to be superior to conventional techniques based on electronic devices in terms of wide bandwidth and high-frequency signals. Conversion from an optical signal to a millimeter/sub-millimeter wave signal is done by a photo-mixer.

  16. Kinematic calibration of orthoglide-type mechanisms

    CERN Document Server

    Pashkevich, Anatoly; Wenger, Philippe

    2006-01-01

    The paper proposes a novel calibration approach for the Orthoglide-type mechanisms based on observations of the manipulator leg parallelism during mo-tions between the prespecified test postures. It employs a low-cost measuring system composed of standard comparator indicators attached to the universal magnetic stands. They are sequentially used for measuring the deviation of the relevant leg location while the manipulator moves the TCP along the Cartesian axes. Using the measured differences, the developed algorithm estimates the joint offsets that are treated as the most essential parameters to be adjusted. The sensitivity of the meas-urement methods and the calibration accuracy are also studied. Experimental re-sults are presented that demonstrate validity of the proposed calibration technique

  17. Redundancy Calibration of Phased Array Stations

    CERN Document Server

    Noorishad, Parisa; van Ardenne, Arnold; van der Hulst, Thijs

    2012-01-01

    Our aim is to assess the benefits and limitations of using the redundant visibility information in regular phased array systems for improving the calibration. Regular arrays offer the possibility to use redundant visibility information to constrain the calibration of the array independent of a sky model and a beam models of the station elements. It requires a regular arrangement in the configuration of array elements and identical beam patterns. We revised a calibration method for phased array stations using the redundant visibility information in the system and applied it successfully to a LOFAR station. The performance and limitations of the method were demonstrated by comparing its use on real and simulated data. The main limitation is the mutual coupling between the station elements, which leads to non-identical beams and stronger baseline dependent noise. Comparing the variance of the estimated complex gains with the Cramer-Rao Bound (CRB) indicates that redundancy is a stable and optimum method for cali...

  18. Timepix detector energy calibration using synchrotron light

    Energy Technology Data Exchange (ETDEWEB)

    Akiba, Kazuyoshi; Vicente, Mateus, E-mail: mateus_vicente@live.com [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Benoit, Mathieu [CERN (France)

    2014-07-01

    The Timepix is a hybrid pixelated detector. It is able to measure the energy of an incident particle on its sensor and provide the particle position within its matrix of 256x256 pixels 55 μm{sup 2} simultaneously. It has direct applications in high energy physics and medical physics. The energy collected by the sensor is translated into an analog electrical pulse and then converted into a digital signal for the readout. To relate in a precise way the digital signal with the actual values of energy, an energy calibration is required. In this work a method of calibration and analysis for the calibration of the detector will be presented. (author)

  19. Calibration of mixed-polarization interferometric observations

    CERN Document Server

    Marti-Vidal, Ivan; Conway, John; Zensus, Anton J

    2016-01-01

    Heterodyne receivers register the sky signal on either a circular polarization basis (where it is split into left-hand and right-hand circular polarization) or a linear polarization basis (where it is split into horizontal and vertical linear polarization). We study the problem of interferometric observations performed with telescopes that observe on different polarization bases, hence producing visibilities that we call "mixed basis" (i.e., linear in one telescope and circular in the other). We present novel algorithms for the proper calibration and treatment of such interferometric observations and test our algorithms with both simulations and real data. The use of our algorithms will be important for the optimum calibration of forthcoming observations with the Atacama Large mm/submm Array (ALMA) in very-long-baseline interferometry (VLBI) mode. Our algorithms will also allow us to optimally calibrate future VLBI observations at very high data rates (i.e., wide bandwidths), where linear-polarization feeds w...

  20. Geometric calibration of high-resolution remote sensing sensors

    Institute of Scientific and Technical Information of China (English)

    LIANG Hong-you; GU Xing-fa; TAO Yu; QIAO Chao-fei

    2007-01-01

    This paper introduces the applications of high-resolution remote sensing imagery and the necessity of geometric calibration for remote sensing sensors considering assurance of the geometric accuracy of remote sensing imagery. Then the paper analyzes the general methodology of geometric calibration. Taking the DMC sensor geometric calibration as an example, the paper discusses the whole calibration procedure. Finally, it gave some concluding remarks on geometric calibration of high-resolution remote sensing sensors.

  1. ELISPOT Assay for Measurement of Antigen-Specific and Polyclonal Antibody Responses.

    Science.gov (United States)

    Lycke, Nils; Coico, Richard

    2015-02-02

    The enzyme-linked immunospot (ELISPOT) assay for detection of antigen-specific and polyclonal antibody responses by single antibody-secreting cells has become the method of choice due to its cell-based quantitative value. Antigen stability and specificity and the diversity of antigens that can be used in the assay have contributed to the translational application of ELISPOT as demonstrated by many FDA-approved clinical tests that employ this technique. In addition, the ELISPOT assay can be used to detect two antigenically different secreted antibodies simultaneously by two-color analysis and offers the unique possibility of quantifying the number of antibody molecules secreted per cell.

  2. Standard test method for nondestructive assay of radioactive material by tomographic gamma scanning

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method describes the nondestructive assay (NDA) of gamma ray emitting radionuclides inside containers using tomographic gamma scanning (TGS). High resolution gamma ray spectroscopy is used to detect and quantify the radionuclides of interest. The attenuation of an external gamma ray transmission source is used to correct the measurement of the emission gamma rays from radionuclides to arrive at a quantitative determination of the radionuclides present in the item. 1.2 The TGS technique covered by the test method may be used to assay scrap or waste material in cans or drums in the 1 to 500 litre volume range. Other items may be assayed as well. 1.3 The test method will cover two implementations of the TGS procedure: (1) Isotope Specific Calibration that uses standards of known radionuclide masses (or activities) to determine system response in a mass (or activity) versus corrected count rate calibration, that applies to only those specific radionuclides for which it is calibrated, and (2) Respo...

  3. Local Volatility Calibration Using An Adjoint Proxy

    Directory of Open Access Journals (Sweden)

    Gabriel TURINICI

    2008-11-01

    Full Text Available We document the calibration of the local volatility in a framework similar to Coleman, Li and Verma. The quality of a surface is assessed through a functional to be optimized; the specificity of the approach is to separate the optimization (performed with any suitable optimization algorithm from the computation of the functional where we use an adjoint (as in L. Jiang et. al. to obtain an approximation; moreover our main calibration variable is the implied volatility (the procedure can also accommodate the Greeks. The procedure performs well on benchmarks from the literature and on FOREX data.

  4. Suggested isosbestic wavelength calibration in clinical analyses.

    Science.gov (United States)

    Hoxter, G

    1979-01-01

    I recommend the use of isosbestic points for conveniently checking the wavelength scale of spectrophotometers in the ultraviolet and visible regions. Colorimetric pH indicators, hemoglobin derivatives, and other radiation-absorbing substances that are convertible into stable isomers of different absorption spectra provide a means for calibrating many different wavelengths by comparing the absorptivities of these isomers in equimolar solutions. The method requires no special precautions and results are independent of substance concentration and temperature between 4 and 45 degrees C. Isosbestic calibration may be important for (e.g.) coenzyme-dependent dehydrogenase activity determinations and in quality assurance programs.

  5. Covariances for Gamma Spectrometer Efficiency Calibrations

    Directory of Open Access Journals (Sweden)

    Williams John G.

    2016-01-01

    Full Text Available An essential part of the efficiency calibration of gamma spectrometers is the determination of uncertainties on the results. Although this is routinely done, it often does not include the correlations between efficiencies at different energies. These can be important in the subsequent use of the detectors to obtain activities for a set of dosimetry reactions. If those values are not mutually independent, then obviously that fact could impact the validity of adjustments or of other conclusions resulting from the analysis. Examples are given of detector calibrations in which the correlations are calculated and propagated through an analysis of measured activities.

  6. Calibration of the solar neutrino detectors

    Energy Technology Data Exchange (ETDEWEB)

    Caccianiga, Barbara; Re, Alessandra Carlotta [Universita degli Studi Milano (Italy); INFN, Milano (Italy)

    2016-04-15

    Calibrations have been crucial for the success of solar neutrino experiments. In this contribution we review the calibration strategies adopted by different solar neutrino experiments. In particular, we will emphasize their common critical aspects and their main differences. In order to do so, we will schematically divide the solar neutrino experiments in two groups: those based on radiochemical techniques, i.e. Homestake, Gallex/GNO, SAGE and those based on real-time techniques i.e. Kamiokande, Super-Kamiokande, SNO, Borexino and KamLAND. (orig.)

  7. Method of biodosimeter calibration for orbital flight

    Science.gov (United States)

    Vladislav, Petrov

    A biodosimetry method, based on estimation of an absorbed dose on the basis of assessment of unstable aberration frequency in the lymphocytes of human's peripheral blood is used broadly in ground conditions for analysis of accidental exposure to personal and citizens. A calibration curve giving the relationship between aberration frequency (generally dicentrics and centric rings) and an absorbed dose in blood samples is used for assessment of crewmember exposure. As a rule gamma - rays corresponding to character of exposure in such accidents are used for these goals. At the same time the space radiation fields are formed mainly by charged particles for which the character of effect on the body cells and tissues differs strongly from that of gamma - rays. As biodosimetry is a relative method of dose measurement it is necessary to obtain a calibration curve corresponding to the conditions in which the measurements will be performed. That is a calibration curve for space application should give a relationship between aberration frequency and a dose formed by radiation field equal to that on the spacecraft trajectory. The report contains a method of obtaining a calibration curve for a case of an orbital flight on the ISS trajectory. The radiobiological basis of the method consists of relationships between chromosomal aberration frequency in human blood lymphocytes and an absorbed dose of protons with four energies (50 MeV, 150 MeV, 400 MeV, 625 MeV) obtained in the accelerator's experiments. Due to the fact that we had experimental data only for protons the calibration curve was obtained for the proton component on the ISS orbit which is mainly formed by trapped protons. Dose spectrum for this energy distribution of protons was calculated and weighting coefficients for taking into account the input of dose of protons with various energies in forming total frequency of chromosomal aberrations were obtained on its basis. The procedure of obtaining such weighting

  8. Electrical Calibration for Calvet Type Microcalorimetry

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The deyjce construction and working principle of Calvet type heat conductive microcalorimetry are generally ineroduced in this paper. Based on previous work, we design a reactor vessel and its electrical calibration equipment according to our special study systems. The heat constant of our improved microalorimetry is gotten by means of electrical calibration on the basis of Tian's equation. The results gotten by in tegration method are identical with ones gotten by peak method. It shows that our improved device works well enough to develop further studies.``

  9. Intercomparison of Laboratory Radiance Calibration Standards

    Science.gov (United States)

    Pavri, Betina; Chrien, Tom; Green, Robert; Williams, Orlesa

    2000-01-01

    Several standards for radiometric calibration were measured repeatedly with a spectroradiometer in order to understand how they compared in accuracy and stability. The tested radiance standards included a NIST 1000 W bulb and halon panel, two calibrated and stabilized integrating spheres, and a cavity blackbody. Results indicate good agreement between the blackbody and 1000 W bulb/spectralon panel, If these two radiance sources are assumed correct, then the integrating spheres did not conform. to their manufacturer-reported radiances in several regions of the spectrum. More detailed measurements am underway to investigate the discrepancy.

  10. Time Calibration of the ANTARES Neutrino Telescope

    CERN Document Server

    Aguilar, J A; Albert, A; André, M; Anghinolfi, M; Anton, G; Anvar, S; Ardid, M; Jesus, A C Assis; Astraatmadja, T; Aubert, J J; Auer, R; Baret, B; Basa, S; Bazzotti, M; Bertin, V; Biagi, S; Bigongiari, C; Bou-Cabo, M; Bouwhuis, M C; Brown, A M; Brunner, J; Busto, J; Camarena, F; Capone, A; Carloganu, C; Carminati, G; Carr, J; Cecchini, S; Charvis, Ph; Chiarusi, T; Circella, M; Costantini, H; Cottini, N; Coyle, P; Curtil, C; Decowski, M P; Dekeyser, I; Deschamps, A; Distefano, C; Donzaud, C; Dornic, D; Drouhin, D; Eberl, T; Emanuele, U; Ernenwein, J P; Escoffier, S; Fehr, F; Flaminio, V; Fritsch, U; Fuda, J L; Galata, S; Gay, P; Giacomelli, G; Gómez-González, J P; Graf, K; Guillard, G; Halladjian, G; Hallewell, G; van Haren, H; Heijboer, A J; Hello, Y; Hernández-Rey, J J; Herold, B; Hössl, J; Hsu, C C; de Jong, M; Kadler, M; Kalantar-Nayestanaki, N; Kalekin, O; Kappes, A; Katz, U; Kooijman, P; Kopper, C; Kouchner, A; Kulikovskiy, V; Lahmann, R; Lamare, P; Larosa, G; Lefèvre, D; Lim, G; Presti, D Lo; Loehner, H; Loucatos, S; Lucarelli, F; Mangano, S; Marcelin, M; Margiotta, A; Martinez-Mora, J A; Mazure, A; Montaruli, T; Morganti, M; Moscoso, L; Motz, H; Naumann, C; Neff, M; Palioselitis, D; Pavalas, G E; Payre, P; Petrovic, J; Piattelli, P; Picot-Clemente, N; Picq, C; Popa, V; Pradier, T; Presani, E; Racca, C; Reed, C; Riccobene, G; Richardt, C; Rujoiu, M; Russo, G V; Salesa, F; Sapienza, P; Schöck, F; Schuller, J P; Shanidze, R; Simeone, F; Spies, A; Spurio, M; Steijger, J J M; Stolarczyk, Th; Taiuti, M; Tamburini, C; Tasca, L; Toscano, S; Vallage, B; Van Elewyck, V; Vannoni, G; Vecchi, M; Vernin, P; Wijnker, G; de Wolf, E; Yepes, H; Zaborov, D; Zornoza, J D; Zúñiga, J

    2010-01-01

    The ANTARES deep-sea neutrino telescope comprises a three-dimensional array of photomultipliers to detect the Cherenkov light induced by upgoing relativistic charged particles originating from neutrino interactions in the vicinity of the detector. The large scattering length of light in the deep sea facilitates an angular resolution of a few tenths of a degree for neutrino energies exceeding 10 TeV. In order to achieve this optimal performance, the time calibration procedures should ensure a relative time calibration between the photomultipliers at the level of about 1ns. The methods developed to attain this level of precision are described.

  11. Time calibration of the ANTARES neutrino telescope

    Science.gov (United States)

    ANTARES Collaboration; Aguilar, J. A.; Al Samarai, I.; Albert, A.; André, M.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; Assis Jesus, A. C.; Astraatmadja, T.; Aubert, J. J.; Auer, R.; Baret, B.; Basa, S.; Bazzotti, M.; Bertin, V.; Biagi, S.; Bigongiari, C.; Bou-Cabo, M.; Bouwhuis, M. C.; Brown, A. M.; Brunner, J.; Busto, J.; Camarena, F.; Capone, A.; Cârloganu, C.; Carminati, G.; Carr, J.; Cecchini, S.; Charvis, Ph.; Chiarusi, T.; Circella, M.; Costantini, H.; Cottini, N.; Coyle, P.; Curtil, C.; Decowski, M. P.; Dekeyser, I.; Deschamps, A.; Distefano, C.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; Emanuele, U.; Ernenwein, J. P.; Escoffier, S.; Fehr, F.; Flaminio, V.; Fritsch, U.; Fuda, J. L.; Galata, S.; Gay, P.; Giacomelli, G.; Gómez-González, J. P.; Graf, K.; Guillard, G.; Halladjian, G.; Hallewell, G.; van Haren, H.; Heijboer, A. J.; Hello, Y.; Hernández-Rey, J. J.; Herold, B.; Hößl, J.; Hsu, C. C.; de Jong, M.; Kadler, M.; Kalantar-Nayestanaki, N.; Kalekin, O.; Kappes, A.; Katz, U.; Kooijman, P.; Kopper, C.; Kouchner, A.; Kulikovskiy, V.; Lahmann, R.; Lamare, P.; Larosa, G.; Lefèvre, D.; Lim, G.; Lo Presti, D.; Loehner, H.; Loucatos, S.; Lucarelli, F.; Mangano, S.; Marcelin, M.; Margiotta, A.; Martinez-Mora, J. A.; Mazure, A.; Montaruli, T.; Morganti, M.; Moscoso, L.; Motz, H.; Naumann, C.; Neff, M.; Palioselitis, D.; Păvălaş, G. E.; Payre, P.; Petrovic, J.; Piattelli, P.; Picot-Clemente, N.; Picq, C.; Popa, V.; Pradier, T.; Presani, E.; Racca, C.; Reed, C.; Riccobene, G.; Richardt, C.; Rujoiu, M.; Russo, G. V.; Salesa, F.; Sapienzap, P.; Schöck, F.; Schuller, J. P.; Shanidze, R.; Simeone, F.; Spies, A.; Spurio, M.; Steijger, J. J. M.; Stolarczyk, Th.; Taiuti, M.; Tamburini, C.; Tasca, L.; Toscano, S.; Vallage, B.; van Elewyck, V.; Vannoni, G.; Vecchi, M.; Vernin, P.; Wijnker, G.; de Wolf, E.; Yepes, H.; Zaborov, D.; Zornoza, J. D.; Zúñiga, J.; ANTARES Collaboration

    2011-02-01

    The ANTARES deep-sea neutrino telescope comprises a three-dimensional array of photomultipliers to detect the Cherenkov light induced by upgoing relativistic charged particles originating from neutrino interactions in the vicinity of the detector. The large scattering length of light in the deep sea facilitates an angular resolution of a few tenths of a degree for neutrino energies exceeding 10 TeV. In order to achieve this optimal performance, the time calibration procedures should ensure a relative time calibration between the photomultipliers at the level of ˜1 ns. The methods developed to attain this level of precision are described.

  12. Astronomical calibration of the Maastrichtian (Late Cretaceous)

    DEFF Research Database (Denmark)

    Husson, Dorothée; Galbrun, Bruno; Laskar, Jacques;

    2011-01-01

    Recent improvements to astronomical modeling of the Solar System have contributed to important refinements of the Cenozoic time scale through astronomical calibration of sedimentary series. We extend this astronomical calibration into the Cretaceous, on the base of the 405 ka orbital eccentricity......, with the presence of cycles corresponding to forcing by precession, obliquity and orbital eccentricity variations. Identification of these cycles leads to the definition of a detailed cyclostratigraphic frame covering nearly 8 Ma, from the upper Campanian to the Cretaceous/Paleogene (K/Pg) boundary. Durations...

  13. Correlation between the genotoxicity endpoints measured by two different genotoxicity assays: comet assay and CBMN assay

    OpenAIRE

    Carina Ladeira; Susana Viegas; Manuel C. Gomes

    2015-01-01

    The cytokinesis-block micronucleus cytome (CBMN) assay is a comprehensive system for measuring DNA damage; cytostasis and cytotoxicity-DNA damage events are scored specifically in once-divided binucleated cells. The endpoints possible to be measured are micronuclei (MN), a biomarker of chromosome breakage and/or whole chromosome loss, nucleoplasmic bridges (NPB), a biomarker of DNA misrepair and/or telomere end-fusions, and nuclear buds (NBUD), a biomarker of elimination of amplified DNA and/...

  14. Development of a thyroperoxidase inhibition assay for high-throughput screening.

    Science.gov (United States)

    Paul, Katie B; Hedge, Joan M; Rotroff, Daniel M; Hornung, Michael W; Crofton, Kevin M; Simmons, Steven O

    2014-03-17

    High-throughput screening (HTPS) assays to detect inhibitors of thyroperoxidase (TPO), the enzymatic catalyst for thyroid hormone (TH) synthesis, are not currently available. Herein, we describe the development of a HTPS TPO inhibition assay. Rat thyroid microsomes and a fluorescent peroxidase substrate, Amplex UltraRed (AUR), were employed in an end-point assay for comparison to the existing kinetic guaiacol (GUA) oxidation assay. Following optimization of assay metrics, including Z', dynamic range, and activity, using methimazole (MMI), the assay was tested with a 21-chemical training set. The potency of MMI-induced TPO inhibition was greater with AUR compared to GUA. The dynamic range and Z' score with MMI were as follows: 127-fold and 0.62 for the GUA assay, 18-fold and 0.86 for the 96-well AUR assay, and 11.5-fold and 0.93 for the 384-well AUR assay. The 384-well AUR assay drastically reduced animal use, requiring one-tenth of the rat thyroid microsomal protein needed for the GUA 96-well format assay. Fourteen chemicals inhibited TPO, with a relative potency ranking of MMI > ethylene thiourea > 6-propylthiouracil > 2,2',4,4'-tetrahydroxy-benzophenone > 2-mercaptobenzothiazole > 3-amino-1,2,4-triazole > genistein > 4-propoxyphenol > sulfamethazine > daidzein > 4-nonylphenol > triclosan > iopanoic acid > resorcinol. These data demonstrate the capacity of this assay to detect diverse TPO inhibitors. Seven chemicals acted as negatives: 2-hydroxy-4-methoxybenzophenone, dibutylphthalate, diethylhexylphthalate, diethylphthalate, 3,5-dimethylpyrazole-1-methanol, methyl 2-methyl-benzoate, and sodium perchlorate. This assay could be used to screen large numbers of chemicals as an integral component of a tiered TH-disruptor screening approach.

  15. Fluorescence polarization assays in high-throughput screening and drug discovery: a review

    Science.gov (United States)

    Hall, Matthew D.; Yasgar, Adam; Peryea, Tyler; Braisted, John C.; Jadhav, Ajit; Simeonov, Anton; Coussens, Nathan P.

    2016-06-01

    The sensitivity of fluorescence polarization (FP) and fluorescence anisotropy (FA) to molecular weight changes has enabled the interrogation of diverse biological mechanisms, ranging from molecular interactions to enzymatic activity. Assays based on FP/FA technology have been widely utilized in high-throughput screening (HTS) and drug discovery due to the homogenous format, robust performance and relative insensitivity to some types of interferences, such as inner filter effects. Advancements in assay design, fluorescent probes, and technology have enabled the application of FP assays to increasingly complex biological processes. Herein we discuss different types of FP/FA assays developed for HTS, with examples to emphasize the diversity of applicable targets. Furthermore, trends in target and fluorophore selection, as well as assay type and format, are examined using annotated HTS assays within the PubChem database. Finally, practical considerations for the successful development and implementation of FP/FA assays for HTS are provided based on experience at our center and examples from the literature, including strategies for flagging interference compounds among a list of hits.

  16. Summary of KOMPSAT-5 Calibration and Validation

    Science.gov (United States)

    Yang, D.; Jeong, H.; Lee, S.; Kim, B.

    2013-12-01

    Korean Multi-Purpose Satellite 5 (KOMPSAT-5), equipped with high resolution X-band (9.66 GHz) Synthetic Aperture Radar (SAR), is planning to be launched on August 22, 2013. With the satellite's primary mission objective being providing Geographical Information System (GIS), Ocean monitoring and Land management, and Disaster and ENvironment monitoring (GOLDEN), it is expected that its applications for scientific research on geographical processes will be extensive. In order to meet its mission objective, the KOMPSAT-5 will provide three different kinds of SAR imaging modes; High Resolution Mode (1 m resolution, 5 km swath), Standard Mode (3 m resolution, 30 km swath), and Wide Swath Mode (20 m resolution, 100 km swath). The KOMPSAT-5 will be operated in a 550 km sun-synchronous, dawn- dusk orbit with a 28-day ground repeat cycle providing valuable image information on Earth surface day-or-night and even in bad weather condition. After successful launch of the satellite, it will go through Launch and Early Operation (LEOP) and In-Orbit Testing (IOT) period about for 6 months to carry out various tests on satellite bus and payload systems. The satellite bus system will be tested during the first 3 weeks after the launch focusing on the Attitude and Orbit Control Subsystem (AOCS) and Integrated GPS Occultation Receiver (IGOR) calibration. With the completion of bus system test, the SAR payload system will be calibrated during initial In-Flight check period (11 weeks) by the joint effort of Thales Alenia Space Italy (TAS-I) and Korea Aerospace Research Institute (KARI). The pointing and relative calibration will be carried out during this period by analyzing the doppler frequency and antenna beam pattern of reflected microwave signal from selected regions with uniform backscattering coefficients (e.g. Amazon rainforest). A dedicated SAR calibration, called primary calibration, will be allocated at the end of LEOP for 12 weeks to perform thorough calibration activities

  17. Calibration Procedures on Oblique Camera Setups

    Science.gov (United States)

    Kemper, G.; Melykuti, B.; Yu, C.

    2016-06-01

    Beside the creation of virtual animated 3D City models, analysis for homeland security and city planning, the accurately determination of geometric features out of oblique imagery is an important task today. Due to the huge number of single images the reduction of control points force to make use of direct referencing devices. This causes a precise camera-calibration and additional adjustment procedures. This paper aims to show the workflow of the various calibration steps and will present examples of the calibration flight with the final 3D City model. In difference to most other software, the oblique cameras are used not as co-registered sensors in relation to the nadir one, all camera images enter the AT process as single pre-oriented data. This enables a better post calibration in order to detect variations in the single camera calibration and other mechanical effects. The shown sensor (Oblique Imager) is based o 5 Phase One cameras were the nadir one has 80 MPIX equipped with a 50 mm lens while the oblique ones capture images with 50 MPix using 80 mm lenses. The cameras are mounted robust inside a housing to protect this against physical and thermal deformations. The sensor head hosts also an IMU which is connected to a POS AV GNSS Receiver. The sensor is stabilized by a gyro-mount which creates floating Antenna -IMU lever arms. They had to be registered together with the Raw GNSS-IMU Data. The camera calibration procedure was performed based on a special calibration flight with 351 shoots of all 5 cameras and registered the GPS/IMU data. This specific mission was designed in two different altitudes with additional cross lines on each flying heights. The five images from each exposure positions have no overlaps but in the block there are many overlaps resulting in up to 200 measurements per points. On each photo there were in average 110 well distributed measured points which is a satisfying number for the camera calibration. In a first step with the help of

  18. CALIBRATION PROCEDURES ON OBLIQUE CAMERA SETUPS

    Directory of Open Access Journals (Sweden)

    G. Kemper

    2016-06-01

    Full Text Available Beside the creation of virtual animated 3D City models, analysis for homeland security and city planning, the accurately determination of geometric features out of oblique imagery is an important task today. Due to the huge number of single images the reduction of control points force to make use of direct referencing devices. This causes a precise camera-calibration and additional adjustment procedures. This paper aims to show the workflow of the various calibration steps and will present examples of the calibration flight with the final 3D City model. In difference to most other software, the oblique cameras are used not as co-registered sensors in relation to the nadir one, all camera images enter the AT process as single pre-oriented data. This enables a better post calibration in order to detect variations in the single camera calibration and other mechanical effects. The shown sensor (Oblique Imager is based o 5 Phase One cameras were the nadir one has 80 MPIX equipped with a 50 mm lens while the oblique ones capture images with 50 MPix using 80 mm lenses. The cameras are mounted robust inside a housing to protect this against physical and thermal deformations. The sensor head hosts also an IMU which is connected to a POS AV GNSS Receiver. The sensor is stabilized by a gyro-mount which creates floating Antenna –IMU lever arms. They had to be registered together with the Raw GNSS-IMU Data. The camera calibration procedure was performed based on a special calibration flight with 351 shoots of all 5 cameras and registered the GPS/IMU data. This specific mission was designed in two different altitudes with additional cross lines on each flying heights. The five images from each exposure positions have no overlaps but in the block there are many overlaps resulting in up to 200 measurements per points. On each photo there were in average 110 well distributed measured points which is a satisfying number for the camera calibration. In a first

  19. CERN Diversity Newsletter - July 2015

    CERN Document Server

    Kaltenhauser, Kristin; CERN. Geneva. HR Department

    2015-01-01

    The first official edition of the CERN Diversity Newsletter, informing on recent and ongoing diversity activities, and interesting reads, videos and other links related to diversity. Subscribe here: https://diversity.web.cern.ch/2015/07/subscribe-diversity-newsletter

  20. Urban thermal diversity

    Institute of Scientific and Technical Information of China (English)

    KoenSTEEMERS; MarylisRAMOS; MariaSINOU

    2003-01-01

    This paper introduces the interrelationships between urban form, microclimate and thermal comfort. It draws on recent research of monitoring, surveying and modelling urban thermal characteristics and proposes a method of mapping urban diversity. Because the urban context provides a rich and varied environment that influences the way we use urban spaces (movement, sequence, activity) and how we feel in them (stimulation, thermal comfort), the aim here is to highlight the notion of diversity. Thus thermal diversity is used as a measure of the urban environment, rather than more conventional spatially or temporally fixed average values.

  1. Calibration of Local Area Weather Radar—Identifying significant factors affecting the calibration

    Science.gov (United States)

    Pedersen, Lisbeth; Jensen, Niels Einar; Madsen, Henrik

    2010-07-01

    A Local Area Weather Radar (LAWR) is an X-band weather radar developed to meet the needs of high resolution rainfall data for hydrological applications. The LAWR system and data processing methods are reviewed in the first part of this paper, while the second part of the paper focuses on calibration. The data processing for handling the partial beam filling issue was found to be essential to the calibration. LAWR uses a different calibration process compared to conventional weather radars, which use a power-law relationship between reflectivity and rainfall rate. Instead LAWR uses a linear relationship of reflectivity and rainfall rate as result of the log transformation carried out by the logarithmic receiver as opposed to the linear receiver of conventional weather radars. Based on rain gauge data for a five month period from a dense network of nine gauges within a 500 × 500 m area and data from a nearby LAWR, the existing calibration method was tested and two new methods were developed. The three calibration methods were verified with three external gauges placed in different locations. It can be concluded that the LAWR calibration uncertainties can be reduced by 50% in two out of three cases when the calibration is based on a factorized 3 parameter linear model instead of a single parameter linear model.

  2. Calibration Issues and Operating System Requirements for Electron-Probe Microanalysis

    Science.gov (United States)

    Carpenter, P.

    2006-01-01

    Instrument purchase requirements and dialogue with manufacturers have established hardware parameters for alignment, stability, and reproducibility, which have helped improve the precision and accuracy of electron microprobe analysis (EPMA). The development of correction algorithms and the accurate solution to quantitative analysis problems requires the minimization of systematic errors and relies on internally consistent data sets. Improved hardware and computer systems have resulted in better automation of vacuum systems, stage and wavelength-dispersive spectrometer (WDS) mechanisms, and x-ray detector systems which have improved instrument stability and precision. Improved software now allows extended automated runs involving diverse setups and better integrates digital imaging and quantitative analysis. However, instrumental performance is not regularly maintained, as WDS are aligned and calibrated during installation but few laboratories appear to check and maintain this calibration. In particular, detector deadtime (DT) data is typically assumed rather than measured, due primarily to the difficulty and inconvenience of the measurement process. This is a source of fundamental systematic error in many microprobe laboratories and is unknown to the analyst, as the magnitude of DT correction is not listed in output by microprobe operating systems. The analyst must remain vigilant to deviations in instrumental alignment and calibration, and microprobe system software must conveniently verify the necessary parameters. Microanalysis of mission critical materials requires an ongoing demonstration of instrumental calibration. Possible approaches to improvements in instrument calibration, quality control, and accuracy will be discussed. Development of a set of core requirements based on discussions with users, researchers, and manufacturers can yield documents that improve and unify the methods by which instruments can be calibrated. These results can be used to

  3. Enzyme-linked immunosorbent assay characterization of basal variation and heritability of systemic microfibrillar-associated protein 4.

    Directory of Open Access Journals (Sweden)

    Susanne Gjørup Sækmose

    Full Text Available BACKGROUND: Microfibrillar-associated protein 4 (MFAP4 is a systemic biomarker that is significantly elevated in samples from patients suffering from hepatic cirrhosis. The protein is generally localized to elastic fibers and other connective tissue fibers in the extracellular matrix (ECM, and variation in systemic MFAP4 (sMFAP4 has the potential to reflect diverse diseases with increased ECM turnover. Here, we aimed to validate an enzyme-linked immunosorbent assay (ELISA for the measurement of sMFAP4 with an emphasis on the robustness of the assay. Moreover, we aimed to determine confounders influencing the basal sMFAP4 variability and the genetic contribution to the basal variation. METHODS: The sandwich ELISA was based on two monoclonal anti-MFAP4 antibodies and was optimized and calibrated with a standard of recombinant MFAP4. The importance of pre-analytical sample handling was evaluated regarding sample tube type, time, and temperature conditions. The mean value structure and variance structure was determined in a twin cohort including 1,417 Danish twins (age 18-67 years by mixed-effect linear regression modeling. RESULTS: The practical working range of the sandwich ELISA was estimated to be 4-75 U/ml. The maximum intra- and inter-assay variation was estimated to be 8.7% and 6.6%, respectively. Sample handling and processing appeared to influence MFAP4 measurements only marginally. The average concentration of sMFAP4 in the serum was 18.9 ± 8.4 (SD U/ml in the twin cohort (95% CI: 18.5-19.4, median sMFAP4 17.3 U/ml. The mean structure model was demonstrated to include waist-hip ratio, age, and cigarette smoking status in interactions with gender. A relatively low heritability of h(2 = 0.24 was found after applying a model including additive genetic factors and shared and non-shared environmental factors. CONCLUSIONS: The described ELISA provides robust measures of the liver fibrosis marker sMFAP4. The low heritability and the relatively

  4. Comparison of colorimetric assays with quantitative amino acid analysis for protein quantification of Generalized Modules for Membrane Antigens (GMMA).

    Science.gov (United States)

    Rossi, Omar; Maggiore, Luana; Necchi, Francesca; Koeberling, Oliver; MacLennan, Calman A; Saul, Allan; Gerke, Christiane

    2015-01-01

    Genetically induced outer membrane particles from Gram-negative bacteria, called Generalized Modules for Membrane Antigens (GMMA), are being investigated as vaccines. Rapid methods are required for estimating the protein content for in-process assays during production. Since GMMA are complex biological structures containing lipid and polysaccharide as well as protein, protein determinations are not necessarily straightforward. We compared protein quantification by Bradford, Lowry, and Non-Interfering assays using bovine serum albumin (BSA) as standard with quantitative amino acid (AA) analysis, the most accurate currently available method for protein quantification. The Lowry assay has the lowest inter- and intra-assay variation and gives the best linearity between protein amount and absorbance. In all three assays, the color yield (optical density per mass of protein) of GMMA was markedly different from that of BSA with a ratio of approximately 4 for the Bradford assay, and highly variable between different GMMA; and approximately 0.7 for the Lowry and Non-Interfering assays, highlighting the need for calibrating the standard used in the colorimetric assay against GMMA quantified by AA analysis. In terms of a combination of ease, reproducibility, and proportionality of protein measurement, and comparability between samples, the Lowry assay was superior to Bradford and Non-Interfering assays for GMMA quantification.

  5. SCIAMACHY Level 1 data: calibration concept and in-flight calibration

    Directory of Open Access Journals (Sweden)

    G. Lichtenberg

    2006-01-01

    Full Text Available The calibration of SCIAMACHY was thoroughly checked since the instrument was launched on-board ENVISAT in February 2002. While SCIAMACHY's functional performance is excellent since launch, a number of technical difficulties have appeared, that required adjustments to the calibration. The problems can be separated into three types: (1 Those caused by the instrument and/or platform environment. Among these are the high water content in the satellite structure and/or MLI layer. This results in the deposition of ice on the detectors in channels 7 and 8 which seriously affects the retrievals in the IR, mostly because of the continuous change of the slit function caused by scattering of the light through the ice layer. Additionally a light leak in channel 7 severely hampers any retrieval from this channel. (2 Problems due to errors in the on-ground calibration and/or data processing affecting for example the radiometric calibration. A new approach based on a mixture of on-ground and in-flight data is shortly described here. (3 Problems caused by principal limitations of the calibration concept, e.g. the possible appearance of spectral structures after the polarisation correction due to unavoidable errors in the determination of atmospheric polarisation. In this paper we give a complete overview of the calibration and problems that still have to be solved. We will also give an indication of the effect of calibration problems on retrievals where possible. Since the operational processing chain is currently being updated and no newly processed data are available at this point in time, for some calibration issues only a rough estimate of the effect on Level 2 products can be given. However, it is the intention of this paper to serve as a future reference for detailed studies into specific calibration issues.

  6. Signal inference with unknown response: calibration uncertainty renormalized estimator

    CERN Document Server

    Dorn, Sebastian; Greiner, Maksim; Selig, Marco; Böhm, Vanessa

    2014-01-01

    The calibration of a measurement device is crucial for every scientific experiment, where a signal has to be inferred from data. We present CURE, the calibration uncertainty renormalized estimator, to reconstruct a signal and simultaneously the instrument's calibration from the same data without knowing the exact calibration, but its covariance structure. The idea of CURE is starting with an assumed calibration to successively include more and more portions of calibration uncertainty into the signal inference equations and to absorb the resulting corrections into renormalized signal (and calibration) solutions. Thereby, the signal inference and calibration problem turns into solving a single system of ordinary differential equations and can be identified with common resummation techniques used in field theories. We verify CURE by applying it to a simplistic toy example and compare it against existent self-calibration schemes, Wiener filter solutions, and Markov Chain Monte Carlo sampling. We conclude that the...

  7. The Calibration Home Base for Imaging Spectrometers

    Directory of Open Access Journals (Sweden)

    Johannes Felix Simon Brachmann

    2016-08-01

    Full Text Available The Calibration Home Base (CHB is an optical laboratory designed for the calibration of imaging spectrometers for the VNIR/SWIR wavelength range. Radiometric, spectral and geometric calibration as well as the characterization of sensor signal dependency on polarization are realized in a precise and highly automated fashion. This allows to carry out a wide range of time consuming measurements in an ecient way. The implementation of ISO 9001 standards in all procedures ensures a traceable quality of results. Spectral measurements in the wavelength range 380–1000 nm are performed to a wavelength uncertainty of +- 0.1 nm, while an uncertainty of +-0.2 nm is reached in the wavelength range 1000 – 2500 nm. Geometric measurements are performed at increments of 1.7 µrad across track and 7.6 µrad along track. Radiometric measurements reach an absolute uncertainty of +-3% (k=1. Sensor artifacts, such as caused by stray light will be characterizable and correctable in the near future. For now, the CHB is suitable for the characterization of pushbroom sensors, spectrometers and cameras. However, it is planned to extend the CHBs capabilities in the near future such that snapshot hyperspectral imagers can be characterized as well. The calibration services of the CHB are open to third party customers from research institutes as well as industry.

  8. In-Flight Pitot-Static Calibration

    Science.gov (United States)

    Foster, John V. (Inventor); Cunningham, Kevin (Inventor)

    2016-01-01

    A GPS-based pitot-static calibration system uses global output-error optimization. High data rate measurements of static and total pressure, ambient air conditions, and GPS-based ground speed measurements are used to compute pitot-static pressure errors over a range of airspeed. System identification methods rapidly compute optimal pressure error models with defined confidence intervals.

  9. Geometric calibration of ERS satellite SAR images

    DEFF Research Database (Denmark)

    Mohr, Johan Jacob; Madsen, Søren Nørvang

    2001-01-01

    Geometric calibration of the European Remote Sensing (ERS) Satellite synthetic aperture radar (SAR) slant range images is important in relation to mapping areas without ground reference points and also in relation to automated processing. The relevant SAR system parameters are discussed...

  10. The External Calibrator for Hydrogen Observatories

    CERN Document Server

    Jacobs, Daniel C; Bowman, Judd; Neben, Abraham R; Stinnett, Benjamin; Turner, Lauren

    2016-01-01

    Multiple instruments are pursuing constraints on dark energy, observing reionization and opening a window on the dark ages through the detection and characterization of the 21cm hydrogen line across the redshift spectrum, from nearby to z=25. These instruments, including CHIME in the sub-meter and HERA in the meter bands, are wide-field arrays with multiple-degree beams, typically operating in transit mode. Accurate knowledge of their primary beams is critical for separation of bright foregrounds from the desired cosmological signals, but difficult to achieve through astronomical observations alone. Previous beam calibration work has focused on model verification and does not address the need of 21cm experiments for routine beam mapping, to the horizon, of the as-built array. We describe the design and methodology of a drone-mounted calibrator, the External Calibrator for Hydrogen Observatories (ECHO), that aims to address this need. We report on a first set of trials to calibrate low-frequency dipoles and co...

  11. Beam Calibration of Radio Telescopes with Drones

    Science.gov (United States)

    Chang, Chihway; Monstein, Christian; Refregier, Alexandre; Amara, Adam; Glauser, Adrian; Casura, Sarah

    2015-11-01

    We present a multi-frequency far-field beam map for the 5m dish telescope at the Bleien Observatory measured using a commercially available drone. We describe the hexacopter drone used in this experiment, the design of the flight pattern, and the data analysis scheme. This is the first application of this calibration method to a single dish radio telescope in the far-field. The high signal-to-noise data allows us to characterise the beam pattern with high accuracy out to at least the 4th side-lobe. The resulting 2D beam pattern is compared with that derived from a more traditional calibration approach using an astronomical calibration source. We discuss the advantages of this method compared to other beam calibration methods. Our results show that this drone-based technique is very promising for ongoing and future radio experiments, where the knowledge of the beam pattern is key to obtaining high-accuracy cosmological and astronomical measurements.

  12. The LOFAR long baseline snapshot calibrator survey

    CERN Document Server

    Moldón, J; Wucknitz, O; Jackson, N; Drabent, A; Carozzi, T; Conway, J; Kapińska, A D; McKean, P; Morabito, L; Varenius, E; Zarka, P; Anderson, J; Asgekar, A; Avruch, I M; Bell, M E; Bentum, M J; Bernardi, G; Best, P; Bîrzan, L; Bregman, J; Breitling, F; Broderick, J W; Brüggen, M; Butcher, H R; Carbone, D; Ciardi, B; de Gasperin, F; de Geus, E; Duscha, S; Eislöffel, J; Engels, D; Falcke, H; Fallows, R A; Fender, R; Ferrari, C; Frieswijk, W; Garrett, M A; Grießmeier, J; Gunst, A W; Hamaker, J P; Hassall, T E; Heald, G; Hoeft, M; Juette, E; Karastergiou, A; Kondratiev, V I; Kramer, M; Kuniyoshi, M; Kuper, G; Maat, P; Mann, G; Markoff, S; McFadden, R; McKay-Bukowski, D; Morganti, R; Munk, H; Norden, M J; Offringa, A R; Orru, E; Paas, H; Pandey-Pommier, M; Pizzo, R; Polatidis, A G; Reich, W; Röttgering, H; Rowlinson, A; Scaife, A M M; Schwarz, D; Sluman, J; Smirnov, O; Stappers, B W; Steinmetz, M; Tagger, M; Tang, Y; Tasse, C; Thoudam, S; Toribio, M C; Vermeulen, R; Vocks, C; van Weeren, R J; White, S; Wise, M W; Yatawatta, S; Zensus, A

    2014-01-01

    Aims. An efficient means of locating calibrator sources for International LOFAR is developed and used to determine the average density of usable calibrator sources on the sky for subarcsecond observations at 140 MHz. Methods. We used the multi-beaming capability of LOFAR to conduct a fast and computationally inexpensive survey with the full International LOFAR array. Sources were pre-selected on the basis of 325 MHz arcminute-scale flux density using existing catalogues. By observing 30 different sources in each of the 12 sets of pointings per hour, we were able to inspect 630 sources in two hours to determine if they possess a sufficiently bright compact component to be usable as LOFAR delay calibrators. Results. Over 40% of the observed sources are detected on multiple baselines between international stations and 86 are classified as satisfactory calibrators. We show that a flat low-frequency spectrum (from 74 to 325 MHz) is the best predictor of compactness at 140 MHz. We extrapolate from our sample to sho...

  13. Calibrating the projection factor for Galactic Cepheids

    CERN Document Server

    Ngeow, Chow-Choong; Nardetto, Nicolas; Marengo, Massimo

    2012-01-01

    The projection factor (p), which converts the radial velocity to pulsational velocity, is an important parameter in the Baade-Wesselink (BW) type analysis and distance scale work. The p-factor is either adopted as a constant or linearly depending on the logarithmic of pulsating periods. The aim of this work is to calibrate the p-factor if a Cepheid has both the BW distance and an independent distance measurement, and examine the p-factor for delta Cephei -- the prototype of classical Cepheids. We calibrated the p-factor for several Galactic Cepheids that have both the latest BW distances and independent distances either from Hipparcos parallaxes or main-sequence fitting distances to Cepheid-hosted stellar clusters. Based on 25 Cepheids, the calibrated p-factor relation is consistent with latest p-factor relation in literature. The calibrated p-factor relation also indicates that this relation may not be linear and may exhibit an intrinsic scatter. We also examined the discrepancy of empirical p-factors for de...

  14. Phase calibration scheme for a ``T'' array

    Science.gov (United States)

    Ramesh, R.; Subramanian, K. R.; Sastry, Ch. V.

    1999-10-01

    A calibration scheme based on closure and redundancy techniques is described for correcting the phase errors in the complex visibilities observed with a T-shaped radio interferometer array. Practical details of the scheme are illustrated with reference to the Gauribidanur radioheliograph (GRH).

  15. Calibration of the ALLEGRO resonant detector

    Energy Technology Data Exchange (ETDEWEB)

    McHugh, Martin P [Department of Physics, Loyola University, New Orleans, Louisiana 70118 (United States); Johnson, Warren W [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Hamilton, William O [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Hanson, Jonathan [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Heng, Ik Siong [University of Glasgow, Glasgow G12 8QQ (United Kingdom); McNeese, Daniel [Department of Physics, Loyola University, New Orleans, Louisiana 70118 (United States); Miller, Phillip [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Nettles, Damon [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Weaver, Jordan [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Zhang Ping [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States)

    2005-09-21

    We describe a method for calibrating the ALLEGRO resonant detector. The resulting response function can be used to transform the observed data backwards to gravitational strain data. These data are the input to a cross-correlation analysis to search for stochastic gravitational waves.

  16. A Calibrated Index of Human Development

    Science.gov (United States)

    Lind, Niels

    2010-01-01

    The weightings of the four component indicators of the UNDP's Human Development Index HDI appear to be arbitrary and have not been given justification. This paper develops a variant of the HDI, calculated to reflect peoples' revealed evaluations of education and the productivity of work. The resulting Calibrated human Development Index CDI has a…

  17. Calibration of Li-glass Detector Efficiency

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Li-glass detector will be used to measure the flux of neutron beam in Gamma-ray Total Absorption Facility(GTAF). We have calibrated the detection efficiency of Li-glass detector in 5SDH-2 accelerator. The beam of neutron was produced by the reaction 7Li

  18. Calibration of the fluxgate CSC vector magnetometers

    DEFF Research Database (Denmark)

    Merayo, José M.G.; Risbo, Torben; Primdahl, Fritz

    1995-01-01

    sensor giving an error corresponding to 5 to 10 nT in full scale field. It rotates as well the CSC sensor axes. In principle this is due to the presence of soft magnetic material. No remanent magnetization has been observed. Hermann Luehr has ratified this fact and recommended a final calibration...

  19. Ground calibrations of Nuclear Compton Telescope

    Science.gov (United States)

    Chiu, Jeng-Lun; Liu, Zhong-Kai; Bandstra, Mark S.; Bellm, Eric C.; Liang, Jau-Shian; Perez-Becker, Daniel; Zoglauer, Andreas; Boggs, Steven E.; Chang, Hsiang-Kuang; Chang, Yuan-Hann; Huang, Minghuey A.; Amman, Mark; Chiang, Shiuan-Juang; Hung, Wei-Che; Lin, Chih-Hsun; Luke, Paul N.; Run, Ray-Shine; Wunderer, Cornelia B.

    2010-07-01

    The Nuclear Compton Telescope (NCT) is a balloon-borne soft gamma ray (0.2-10 MeV) telescope designed to study astrophysical sources of nuclear line emission and polarization. The heart of NCT is an array of 12 cross-strip germanium detectors, designed to provide 3D positions for each photon interaction with full 3D position resolution to imaging, effectively reduces background, and enables the measurement of polarization. The keys to Compton imaging with NCT's detectors are determining the energy deposited in the detector at each strip and tracking the gamma-ray photon interaction within the detector. The 3D positions are provided by the orthogonal X and Y strips, and by determining the interaction depth using the charge collection time difference (CTD) between the anode and cathode. Calibrations of the energy as well as the 3D position of interactions have been completed, and extensive calibration campaigns for the whole system were also conducted using radioactive sources prior to our flights from Ft. Sumner, New Mexico, USA in Spring 2009, and from Alice Springs, Australia in Spring 2010. Here we will present the techniques and results of our ground calibrations so far, and then compare the calibration results of the effective area throughout NCT's field of view with Monte Carlo simulations using a detailed mass model.

  20. Retained Gas Sampler Calibration and Simulant Tests

    Energy Technology Data Exchange (ETDEWEB)

    CRAWFORD, B.A.

    2000-01-05

    This test plan provides a method for calibration of the retained gas sampler (RGS) for ammonia gas analysis. Simulant solutions of ammonium hydroxide at known concentrations will be diluted with isotopically labeled 0.04 M ammonium hydroxide solution. Sea sand solids will also be mixed with ammonium hydroxide solution and diluent to determine the accuracy of the system for ammonia gas analysis.